UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

1

OFFICE OF PREVENTION, PESTICIDES AND 

TOXIC SUBSTANCES 

 

PC Code No.: 128807 

DP Barcode: 357895, 357900 

 

MEMORANDUM Date: May 11, 2009 

Subject: Section 3 new use registration for gamma-Cyhalothrin in the product COBALTTM

on wheat in the following states: Alabama, Arkansas, Georgia, Illinois, Indiana, 

Iowa, Kentucky, Louisiana, Michigan, Missouri, North Carolina, Ohio, South 

Carolina, Tennessee, Virginia, and Wisconsin. 

. 

To: Venus Eagle, (703-308-8045) 

 Akiva Abramovitch, RM Reviewer 

Registration Division (7505P) 

From: Joseph DeCant, Ecologist 

 Environmental Risk Branch V 

Environmental Fate and Effects Division (7507P) 

Through: Mah Shamim, Ph.D., Chief 

Environmental Risk Branch V 

Environmental Fate and Effects Division (7507P) 

The previously submitted assessment for the use of gamma-cyhalothrin DP Barcodes D289801, 

289799, 289797, 289794, 289798, and 288057, can be used in place of a new assessment for the 

currently proposed uses on wheat in the following states: Alabama, Arkansas, Georgia, Illinois 

Indiana, Iowa, Kentucky, Louisiana, Michigan, Missouri, North Carolina, Ohio, South Carolina, 

Tennessee, Virginia, and Wisconsin. With a maximum seasonal use rate of 0.0176 lbs ai/A, the 

currently proposed maximum use rate is less than the seasonal maximum use rate of 0.03 lbs 

ai/A on wheat already registered for gamma-cyhalothrin in the Prolex formulation for the entire 

United States. These use rates are covered in the previous assessments and risks should be 

similar. A listing is attached of endangered species that may potentially be affected by direct or 

indirect effects. 
−2−

Species Occurrence in Selected States and Selected Taxa

No species were excluded

All Medium Types Reported

Mammal, Marine mml, Bird, Amphibian, Reptile, Fish, Crustacean, Bivalve, Gastropod, 

Arachnid, Insect, Dicot, Monocot

Alabama, Arkansas, Georgia, Illinois, Indiana, Iowa, Kentucky, Louisiana, Michigan, Missouri, 

North Carolina, Ohio, South Carolina, Tennessee, Virginia, Wisconsin

Alabama ( 88) species: CH

 Amphibian

Salamander, Flatwoods Ambystoma cingulatum T Terrestrial, Freshwater, No

Vernal pool

Salamander, Red Hills Phaeognathus hubrichti T Terrestrial, Freshwater No

 Bird

Plover, Piping Charadrius melodus E Terrestrial Yes

Stork, Wood Mycteria americana E Terrestrial No

Woodpecker, Red-cockaded Picoides borealis E Terrestrial No

 Bivalve

Combshell, Southern (=Penitent Epioblasma penita E Freshwater No

mussel)

Combshell, Upland Epioblasma metastriata E Freshwater Yes

Kidneyshell, Triangular Ptychobranchus greenii E Freshwater Yes

Mucket, Orangenacre Lampsilis perovalis T Freshwater Yes

Mucket, Pink (Pearlymussel) Lampsilis abrupta E Freshwater No

Mussel, Acornshell Southern Epioblasma othcaloogensis E Freshwater Yes

Mussel, Alabama Moccasinshell Medionidus acutissimus T Freshwater Yes

Mussel, Coosa Moccasinshell Medionidus parvulus E Freshwater Yes

Mussel, Cumberland Combshell Epioblasma brevidens E Freshwater Yes

Mussel, Dark Pigtoe Pleurobema furvum E Freshwater Yes

Mussel, Fine-lined Pocketbook Lampsilis altilis T Freshwater Yes

Mussel, Fine-rayed Pigtoe Fusconaia cuneolus E Freshwater No

Mussel, Flat Pigtoe (=Marshall's Pleurobema marshalli E Freshwater No

Mussel)

Mussel, Heavy Pigtoe (=Judge Pleurobema taitianum E Freshwater No

Tait's Mussel)

Mussel, Heelsplitter Inflated Potamilus inflatus T Freshwater No

Mussel, Ovate Clubshell Pleurobema perovatum E Freshwater Yes

Mussel, Ring Pink (=Golf Stick Obovaria retusa E Freshwater No

Mussel, Rough Pigtoe Pleurobema plenum E Freshwater No

Mussel, Shiny Pigtoe Fusconaia cor E Freshwater No

Mussel, Shiny-rayed Pocketbook Lampsilis subangulata E Freshwater No

Mussel, Southern Clubshell Pleurobema decisum E Freshwater Yes
−3−

Mussel, Southern Pigtoe Pleurobema georgianum E Freshwater Yes

Pearlymussel, Alabama Lamp Lampsilis virescens E Freshwater No

Pearlymussel, Cracking Hemistena lata E Freshwater No

Pearlymussel, Cumberland Quadrula intermedia E Freshwater No

Monkeyface

Pearlymussel, Orange-footed Plethobasus cooperianus E Freshwater No

Pearlymussel, Pale Lilliput Toxolasma cylindrellus E Freshwater No

Pearlymussel, Turgid-blossom Epioblasma turgidula E Freshwater No

Pearlymussel, White Wartyback Plethobasus cicatricosus E Freshwater No

Stirrupshell Quadrula stapes E Freshwater No

 Crustacean

Shrimp, Alabama Cave Palaemonias alabamae E Freshwater No

 Dicot

Amphianthus, Little Amphianthus pusillus T Freshwater No

Barbara Buttons, Mohr's Marshallia mohrii T Terrestrial No

Bladderpod, Lyrate Lesquerella lyrata T Terrestrial No

Clover, Leafy Prairie Dalea foliosa E Terrestrial No

Harperella Ptilimnium nodosum E Freshwater No

Leather-flower, Alabama Clematis socialis E Terrestrial No

Leather-flower, Morefield's Clematis morefieldii E Terrestrial No

Pitcher-plant, Alabama Canebrake Sarracenia rubra alabamensis E Terrestrial, Freshwater No

Pitcher-plant, Green Sarracenia oreophila E Terrestrial, Freshwater No

Potato-bean, Price's Apios priceana T Terrestrial No

 Fish

Cavefish, Alabama Speoplatyrhinus poulsoni E Freshwater Yes

Chub, Spotfin Erimonax monachus T Freshwater Yes

Darter, Boulder Etheostoma wapiti E Freshwater No

Darter, Goldline Percina aurolineata T Freshwater No

Darter, Slackwater Etheostoma boschungi T Freshwater Yes

Darter, Snail Percina tanasi T Freshwater No

Darter, Vermilion Etheostoma chermocki E Freshwater No

Darter, Watercress Etheostoma nuchale E Freshwater No

Madtom, Yellowfin Noturus flavipinnis T Freshwater Yes

Sculpin, Pygmy Cottus paulus (=pygmaeus) T Freshwater No

Shiner, Blue Cyprinella caerulea T Freshwater No

Shiner, Cahaba Notropis cahabae E Freshwater No

Shiner, Palezone Notropis albizonatus E Freshwater No

Sturgeon, Alabama Scaphirhynchus suttkusi E Freshwater No

Sturgeon, Gulf Acipenser oxyrinchus desotoi T Freshwater, Saltwater Yes

 Gastropod

Campeloma, Slender Campeloma decampi E Freshwater No
−4−

Elimia, Lacy Elimia crenatella T Freshwater No

Pebblesnail, Flat Lepyrium showalteri E Freshwater No

Riversnail, Anthony's Athearnia anthonyi E Freshwater No

Rocksnail, Painted Leptoxis taeniata T Freshwater No

Rocksnail, Plicate Leptoxis plicata E Freshwater No

Rocksnail, Round Leptoxis ampla T Freshwater No

Snail, Armored Pyrgulopsis (=Marstonia) pachyta E Freshwater No

Snail, Lioplax Cylindrical Lioplax cyclostomaformis E Freshwater No

Snail, Tulotoma Tulotoma magnifica E Terrestrial No

 Mammal

Bat, Gray Myotis grisescens E Terrestrial, No

Subterraneous

Bat, Indiana Myotis sodalis E Terrestrial, Yes

Subterraneous

Mouse, Alabama Beach Peromyscus polionotus E Terrestrial, Coastal Yes

Mouse, Perdido Key Beach Peromyscus polionotus E Coastal Yes

 Marine mml

Whale, Finback Balaenoptera physalus E Saltwater No

Whale, Humpback Megaptera novaeangliae E Saltwater No

 Monocot

Grass, Tennessee Yellow-eyed Xyris tennesseensis E Terrestrial No

Trillium, Relict Trillium reliquum E Terrestrial No

Water-plantain, Kral's Sagittaria secundifolia T Freshwater No

 Reptile

Sea turtle, hawksbill Eretmochelys imbricata E Saltwater, Coastal Yes

Sea turtle, Kemp's ridley Lepidochelys kempii E Saltwater, Coastal No

Sea turtle, leatherback Dermochelys coriacea E Saltwater, Coastal Yes

Sea turtle, loggerhead Caretta caretta T Saltwater, Coastal No

Snake, Eastern Indigo Drymarchon corais couperi T Terrestrial Yes

Tortoise, Gopher Gopherus polyphemus T Terrestrial No

Turtle, Alabama Red-bellied Pseudemys alabamensis E Terrestrial, Freshwater No

Turtle, Flattened Musk Sternotherus depressus T Terrestrial, Freshwater No

Arkansas ( 22) species: CH

 Bird

Tern, Interior (population) Least Sterna antillarum E Terrestrial No

Woodpecker, Red-cockaded Picoides borealis E Terrestrial No

 Bivalve

Fatmucket, Arkansas Lampsilis powelli T Freshwater No

Mucket, Pink (Pearlymussel) Lampsilis abrupta E Freshwater No

Mussel, Scaleshell Leptodea leptodon E Freshwater No

Mussel, Speckled Pocketbook Lampsilis streckeri E Freshwater No

Pearlymussel, Fat Pocketbook Potamilus capax E Freshwater No
−5−

Rock-pocketbook, Ouachita Arkansia wheeleri E Freshwater No

(=Wheeler's pm)

 Crustacean

Crayfish, Cave (Cambarus Cambarus aculabrum E Freshwater No

Crayfish, Cave (Cambarus Cambarus zophonastes E Freshwater No

zophonastes)

 Dicot

Bladderpod, Missouri Lesquerella filiformis T Terrestrial No

Fruit, Earth (=geocarpon) Geocarpon minimum T Terrestrial No

Harperella Ptilimnium nodosum E Freshwater No

Pondberry Lindera melissifolia E Terrestrial No

 Fish

Cavefish, Ozark Amblyopsis rosae T Freshwater No

Darter, Leopard Percina pantherina T Freshwater Yes

Sturgeon, Pallid Scaphirhynchus albus E Freshwater No

 Gastropod

Shagreen, Magazine Mountain Mesodon magazinensis T Terrestrial No

 Insect

Beetle, American Burying Nicrophorus americanus E Terrestrial No

 Mammal

Bat, Gray Myotis grisescens E Terrestrial, No

Subterraneous

Bat, Indiana Myotis sodalis E Terrestrial, Yes

Subterraneous

Bat, Ozark Big-eared Corynorhinus (=Plecotus) E Terrestrial, No

townsendii ingens Subterraneous

Georgia ( 63) species: CH

 Amphibian

Salamander, Flatwoods Ambystoma cingulatum T Terrestrial, Freshwater, No

Vernal pool

 Bird

Plover, Piping Charadrius melodus E Terrestrial Yes

Stork, Wood Mycteria americana E Terrestrial No

Warbler (=Wood), Kirtland's Dendroica kirtlandii E Terrestrial No

Woodpecker, Red-cockaded Picoides borealis E Terrestrial No

 Bivalve

Bankclimber, Purple Elliptoideus sloatianus T Freshwater No

Combshell, Upland Epioblasma metastriata E Freshwater Yes

Fanshell Cyprogenia stegaria E Freshwater No

Kidneyshell, Triangular Ptychobranchus greenii E Freshwater Yes

Mucket, Pink (Pearlymussel) Lampsilis abrupta E Freshwater No

Mussel, Acornshell Southern Epioblasma othcaloogensis E Freshwater Yes

Mussel, Alabama Moccasinshell Medionidus acutissimus T Freshwater Yes
−6−

Mussel, Coosa Moccasinshell Medionidus parvulus E Freshwater Yes

Mussel, Fat Threeridge Amblema neislerii E Freshwater No

Mussel, Fine-lined Pocketbook Lampsilis altilis T Freshwater Yes

Mussel, Gulf Moccasinshell Medionidus penicillatus E Freshwater No

Mussel, Oval Pigtoe Pleurobema pyriforme E Freshwater No

Mussel, Ovate Clubshell Pleurobema perovatum E Freshwater Yes

Mussel, Shiny-rayed Pocketbook Lampsilis subangulata E Freshwater No

Mussel, Southern Clubshell Pleurobema decisum E Freshwater Yes

Mussel, Southern Pigtoe Pleurobema georgianum E Freshwater Yes

 Dicot

Amphianthus, Little Amphianthus pusillus T Freshwater No

Barbara Buttons, Mohr's Marshallia mohrii T Terrestrial No

Campion, Fringed Silene polypetala E Terrestrial No

Dropwort, Canby's Oxypolis canbyi E Terrestrial, Freshwater No

Harperella Ptilimnium nodosum E Freshwater No

Pitcher-plant, Green Sarracenia oreophila E Terrestrial, Freshwater No

Pondberry Lindera melissifolia E Terrestrial No

Rattleweed, Hairy Baptisia arachnifera E Terrestrial No

Skullcap, Large-flowered Scutellaria montana T Terrestrial No

Spiraea, Virginia Spiraea virginiana T Terrestrial No

Sumac, Michaux's Rhus michauxii E Terrestrial No

 Fish

Chub, Spotfin Erimonax monachus T Freshwater Yes

Darter, Amber Percina antesella E Freshwater Yes

Darter, Cherokee Etheostoma scotti T Freshwater No

Darter, Etowah Etheostoma etowahae E Freshwater No

Darter, Goldline Percina aurolineata T Freshwater No

Darter, Snail Percina tanasi T Freshwater No

Logperch, Conasauga Percina jenkinsi E Freshwater Yes

Madtom, Yellowfin Noturus flavipinnis T Freshwater Yes

Shiner, Blue Cyprinella caerulea T Freshwater No

Sturgeon, Gulf Acipenser oxyrinchus desotoi T Freshwater, Saltwater Yes

Sturgeon, Shortnose Acipenser brevirostrum E Freshwater, Saltwater No

 Insect

Beetle, American Burying Nicrophorus americanus E Terrestrial No

 Mammal

Bat, Gray Myotis grisescens E Terrestrial, No

Subterraneous

Bat, Indiana Myotis sodalis E Terrestrial, Yes

Subterraneous

Bat, Virginia Big-eared Corynorhinus (=Plecotus) E Terrestrial, Yes

townsendii virginianus Subterraneous
−7−

 Marine mml

Manatee, West Indian Trichechus manatus E Saltwater Yes

Whale, Finback Balaenoptera physalus E Saltwater No

Whale, Humpback Megaptera novaeangliae E Saltwater No

Whale, North Atlantic right Eubalaena glacialis (incl. E Saltwater Yes

 Monocot

Grass, Tennessee Yellow-eyed Xyris tennesseensis E Terrestrial No

Pink, Swamp Helonias bullata T Terrestrial, Freshwater No

Pogonia, Small Whorled Isotria medeoloides T Terrestrial No

Trillium, Persistent Trillium persistens E Terrestrial No

Trillium, Relict Trillium reliquum E Terrestrial No

Water-plantain, Kral's Sagittaria secundifolia T Freshwater No

 Reptile

Sea turtle, green Chelonia mydas E Saltwater Yes

Sea turtle, hawksbill Eretmochelys imbricata E Saltwater, Coastal Yes

Sea turtle, Kemp's ridley Lepidochelys kempii E Saltwater, Coastal No

Sea turtle, leatherback Dermochelys coriacea E Saltwater, Coastal Yes

Sea turtle, loggerhead Caretta caretta T Saltwater, Coastal No

Snake, Eastern Indigo Drymarchon corais couperi T Terrestrial Yes

Illinois ( 25) species: CH

 Bird

Plover, Piping Charadrius melodus E Terrestrial Yes

Tern, Interior (population) Least Sterna antillarum E Terrestrial No

 Bivalve

Fanshell Cyprogenia stegaria E Freshwater No

Mucket, Pink (Pearlymussel) Lampsilis abrupta E Freshwater No

Mussel, Clubshell Pleurobema clava E Freshwater No

Pearlymussel, Fat Pocketbook Potamilus capax E Freshwater No

Pearlymussel, Higgins' Eye Lampsilis higginsii E Freshwater No

Pearlymussel, Orange-footed Plethobasus cooperianus E Freshwater No

Pearlymussel, White Wartyback Plethobasus cicatricosus E Freshwater No

 Crustacean

Amphipod, Illinois Cave Gammarus acherondytes E Freshwater, No

Subterraneous

 Dicot

Aster, Decurrent False Boltonia decurrens T Terrestrial, Freshwater No

Clover, Leafy Prairie Dalea foliosa E Terrestrial No

Clover, Prairie Bush Lespedeza leptostachya T Terrestrial No

Daisy, Lakeside Hymenoxys herbacea T Freshwater No

Milkweed, Mead's Asclepias meadii T Terrestrial No

Potato-bean, Price's Apios priceana T Terrestrial No
−8−

Thistle, Pitcher's Cirsium pitcheri T Terrestrial No

 Fish

Sturgeon, Pallid Scaphirhynchus albus E Freshwater No

 Gastropod

Snail, Iowa Pleistocene Discus macclintocki E Terrestrial No

 Insect

Butterfly, Karner Blue Lycaeides melissa samuelis E Terrestrial No

Dragonfly, Hine's Emerald Somatochlora hineana E Terrestrial, Freshwater Yes

 Mammal

Bat, Gray Myotis grisescens E Terrestrial, No

Subterraneous

Bat, Indiana Myotis sodalis E Terrestrial, Yes

Subterraneous

 Monocot

Orchid, Eastern Prairie Fringed Platanthera leucophaea T Terrestrial No

Pogonia, Small Whorled Isotria medeoloides T Terrestrial No

Indiana ( 23) species: CH

 Bird

Plover, Piping Charadrius melodus E Terrestrial Yes

Tern, Interior (population) Least Sterna antillarum E Terrestrial No

 Bivalve

Fanshell Cyprogenia stegaria E Freshwater No

Mucket, Pink (Pearlymussel) Lampsilis abrupta E Freshwater No

Mussel, Clubshell Pleurobema clava E Freshwater No

Mussel, Ring Pink (=Golf Stick Obovaria retusa E Freshwater No

Mussel, Rough Pigtoe Pleurobema plenum E Freshwater No

Pearlymussel, Fat Pocketbook Potamilus capax E Freshwater No

Pearlymussel, Orange-footed Plethobasus cooperianus E Freshwater No

Pearlymussel, Tubercled-blossom Epioblasma torulosa torulosa E Freshwater No

Pearlymussel, White Cat's Paw Epioblasma obliquata perobliqua E Freshwater No

Pearlymussel, White Wartyback Plethobasus cicatricosus E Freshwater No

Riffleshell, Northern Epioblasma torulosa rangiana E Freshwater No

 Dicot

Clover, Running Buffalo Trifolium stoloniferum E Terrestrial No

Goldenrod, Short's Solidago shortii E Terrestrial No

Milkweed, Mead's Asclepias meadii T Terrestrial No

Thistle, Pitcher's Cirsium pitcheri T Terrestrial No

 Insect

Butterfly, Karner Blue Lycaeides melissa samuelis E Terrestrial No

Butterfly, Mitchell's Satyr Neonympha mitchellii mitchellii E Terrestrial, Perm. No

wetland

 Mammal
−9−

Bat, Gray Myotis grisescens E Terrestrial, No

Subterraneous

Bat, Indiana Myotis sodalis E Terrestrial, Yes

Subterraneous

 Monocot

Orchid, Eastern Prairie Fringed Platanthera leucophaea T Terrestrial No

 Reptile

Snake, Northern Copperbelly Water Nerodia erythrogaster neglecta T Terrestrial, Freshwater No

Iowa ( 13) species: CH

 Bird

Plover, Piping Charadrius melodus E Terrestrial Yes

Tern, Interior (population) Least Sterna antillarum E Terrestrial No

 Bivalve

Pearlymussel, Fat Pocketbook Potamilus capax E Freshwater No

Pearlymussel, Higgins' Eye Lampsilis higginsii E Freshwater No

 Dicot

Clover, Prairie Bush Lespedeza leptostachya T Terrestrial No

Milkweed, Mead's Asclepias meadii T Terrestrial No

Monkshood, Northern Wild Aconitum noveboracense T Terrestrial No

 Fish

Shiner, Topeka Notropis topeka (=tristis) E Freshwater Yes

Sturgeon, Pallid Scaphirhynchus albus E Freshwater No

 Gastropod

Snail, Iowa Pleistocene Discus macclintocki E Terrestrial No

 Mammal

Bat, Indiana Myotis sodalis E Terrestrial, Yes

Subterraneous

 Monocot

Orchid, Eastern Prairie Fringed Platanthera leucophaea T Terrestrial No

Orchid, Western Prairie Fringed Platanthera praeclara T Terrestrial No

 

Kentucky ( 49) species: CH

 Bird

Plover, Piping Charadrius melodus E Terrestrial Yes

Tern, Interior (population) Least Sterna antillarum E Terrestrial No

Warbler (=Wood), Kirtland's Dendroica kirtlandii E Terrestrial No

Warbler, Bachman's Vermivora bachmanii E Terrestrial No

Woodpecker, Ivory-billed Campephilus principalis E Terrestrial No

Woodpecker, Red-cockaded Picoides borealis E Terrestrial No

 Bivalve

Fanshell Cyprogenia stegaria E Freshwater No
−10−

Mucket, Pink (Pearlymussel) Lampsilis abrupta E Freshwater No

Mussel, Clubshell Pleurobema clava E Freshwater No

Mussel, Cumberland Combshell Epioblasma brevidens E Freshwater Yes

Mussel, Cumberland Elktoe Alasmidonta atropurpurea E Freshwater Yes

Mussel, Oyster Epioblasma capsaeformis E Freshwater Yes

Mussel, Ring Pink (=Golf Stick Obovaria retusa E Freshwater No

Mussel, Rough Pigtoe Pleurobema plenum E Freshwater No

Mussel, Winged Mapleleaf Quadrula fragosa E Freshwater No

Pearlymussel, Appalachian Quadrula sparsa E Freshwater No

Monkeyface

Pearlymussel, Cracking Hemistena lata E Freshwater No

Pearlymussel, Cumberland Bean Villosa trabalis E Freshwater No

Pearlymussel, Dromedary Dromus dromas E Freshwater No

Pearlymussel, Fat Pocketbook Potamilus capax E Freshwater No

Pearlymussel, Little-wing Pegias fabula E Freshwater No

Pearlymussel, Orange-footed Plethobasus cooperianus E Freshwater No

Pearlymussel, Purple Cat's Paw Epioblasma obliquata obliquata E Freshwater No

Pearlymussel, Tubercled-blossom Epioblasma torulosa torulosa E Freshwater No

Pearlymussel, White Wartyback Plethobasus cicatricosus E Freshwater No

Pearlymussel, Yellow-blossom Epioblasma florentina florentina E Freshwater No

Riffleshell, Northern Epioblasma torulosa rangiana E Freshwater No

Riffleshell, Tan Epioblasma florentina walkeri E Freshwater No

(=E. walkeri)

 Crustacean

Shrimp, Kentucky Cave Palaemonias ganteri E Freshwater Yes

 Dicot

Chaffseed, American Schwalbea americana E Terrestrial No

Clover, Running Buffalo Trifolium stoloniferum E Terrestrial No

Goldenrod, Short's Solidago shortii E Terrestrial No

Goldenrod, White-haired Solidago albopilosa T Terrestrial No

Potato-bean, Price's Apios priceana T Terrestrial No

Rock-cress, Braun's Arabis perstellata E. L. Braun var. E Terrestrial Yes

 ampla Rollins

Rock-cress, Small Arabis perstellata E. L. Braun var. E Terrestrial Yes

 perstellata Fernald

Rosemary, Cumberland Conradina verticillata T Terrestrial No

Sandwort, Cumberland Arenaria cumberlandensis E Terrestrial No

Spiraea, Virginia Spiraea virginiana T Terrestrial No

 Fish

Dace, Blackside Phoxinus cumberlandensis T Freshwater No

Darter, Bluemask (=jewel) Etheostoma sp. E Freshwater No

Darter, Relict Etheostoma chienense E Freshwater No
−11−

Shiner, Palezone Notropis albizonatus E Freshwater No

Sturgeon, Pallid Scaphirhynchus albus E Freshwater No

 Insect

Beetle, American Burying Nicrophorus americanus E Terrestrial No

 Mammal

Bat, Gray Myotis grisescens E Terrestrial, No

Subterraneous

Bat, Indiana Myotis sodalis E Terrestrial, Yes

Subterraneous

Bat, Virginia Big-eared Corynorhinus (=Plecotus) E Terrestrial, Yes

townsendii virginianus Subterraneous

Wolf, Red Canis rufus E Terrestrial No

Louisiana ( 24) species: CH

 Bird

Pelican, Brown Pelecanus occidentalis E Terrestrial No

Plover, Piping Charadrius melodus E Terrestrial Yes

Tern, California Least Sterna antillarum browni E Terrestrial No

Tern, Interior (population) Least Sterna antillarum E Terrestrial No

Woodpecker, Red-cockaded Picoides borealis E Terrestrial No

 Bivalve

Mucket, Pink (Pearlymussel) Lampsilis abrupta E Freshwater No

Mussel, Heelsplitter Inflated Potamilus inflatus T Freshwater No

Pearlshell, Louisiana Margaritifera hembeli T Freshwater No

 Dicot

Chaffseed, American Schwalbea americana E Terrestrial No

Fruit, Earth (=geocarpon) Geocarpon minimum T Terrestrial No

 Fish

Sturgeon, Gulf Acipenser oxyrinchus desotoi T Freshwater, Saltwater Yes

Sturgeon, Pallid Scaphirhynchus albus E Freshwater No

 Mammal

Bear, Louisiana Black Ursus americanus luteolus T Terrestrial No

Jaguar Panthera onca E Terrestrial No

 Marine mml

Manatee, West Indian Trichechus manatus E Saltwater Yes

Whale, Finback Balaenoptera physalus E Saltwater No

Whale, Humpback Megaptera novaeangliae E Saltwater No

 Reptile

Sea turtle, green Chelonia mydas E Saltwater Yes

Sea turtle, hawksbill Eretmochelys imbricata E Saltwater, Coastal Yes

Sea turtle, Kemp's ridley Lepidochelys kempii E Saltwater, Coastal No

Sea turtle, leatherback Dermochelys coriacea E Saltwater, Coastal Yes

Sea turtle, loggerhead Caretta caretta T Saltwater, Coastal No
−12−

Tortoise, Gopher Gopherus polyphemus T Terrestrial No

Turtle, Ringed Sawback Graptemys oculifera T Terrestrial, Freshwater No

Michigan ( 18) species: CH

 Bird

Plover, Piping Charadrius melodus E Terrestrial Yes

Warbler (=Wood), Kirtland's Dendroica kirtlandii E Terrestrial No

 Bivalve

Mussel, Clubshell Pleurobema clava E Freshwater No

Riffleshell, Northern Epioblasma torulosa rangiana E Freshwater No

 Dicot

Daisy, Lakeside Hymenoxys herbacea T Freshwater No

Goldenrod, Houghton's Solidago houghtonii T Terrestrial No

Monkey-flower, Michigan Mimulus glabratus var. E Terrestrial, Freshwater No

michiganensis

Thistle, Pitcher's Cirsium pitcheri T Terrestrial No

 Insect

Beetle, Hungerford's Crawling Brychius hungerfordi E Freshwater No

Butterfly, Karner Blue Lycaeides melissa samuelis E Terrestrial No

Butterfly, Mitchell's Satyr Neonympha mitchellii mitchellii E Terrestrial, Perm. No

wetland

Dragonfly, Hine's Emerald Somatochlora hineana E Terrestrial, Freshwater Yes

 Mammal

Bat, Indiana Myotis sodalis E Terrestrial, Yes

Subterraneous

Lynx, Canada Lynx canadensis T Terrestrial No

 Monocot

Iris, Dwarf Lake Iris lacustris T Terrestrial No

Orchid, Eastern Prairie Fringed Platanthera leucophaea T Terrestrial No

Pogonia, Small Whorled Isotria medeoloides T Terrestrial No

 Reptile

Snake, Northern Copperbelly Water Nerodia erythrogaster neglecta T Terrestrial, Freshwater No

Missouri ( 29) species: CH

 Bird

Plover, Piping Charadrius melodus E Terrestrial Yes

Tern, Interior (population) Least Sterna antillarum E Terrestrial No

 Bivalve

Mucket, Pink (Pearlymussel) Lampsilis abrupta E Freshwater No

Mussel, Scaleshell Leptodea leptodon E Freshwater No

Mussel, Winged Mapleleaf Quadrula fragosa E Freshwater No

Pearlymussel, Curtis' Epioblasma florentina curtisii E Freshwater No

Pearlymussel, Fat Pocketbook Potamilus capax E Freshwater No

Pearlymussel, Higgins' Eye Lampsilis higginsii E Freshwater No
−13−

 Crustacean

Crayfish, Cave (Cambarus Cambarus aculabrum E Freshwater No

 Dicot

Aster, Decurrent False Boltonia decurrens T Terrestrial, Freshwater No

Bladderpod, Missouri Lesquerella filiformis T Terrestrial No

Clover, Running Buffalo Trifolium stoloniferum E Terrestrial No

Fruit, Earth (=geocarpon) Geocarpon minimum T Terrestrial No

Milkweed, Mead's Asclepias meadii T Terrestrial No

Pondberry Lindera melissifolia E Terrestrial No

Sneezeweed, Virginia Helenium virginicum T Vernal pool No

 Fish

Cavefish, Ozark Amblyopsis rosae T Freshwater No

Chub, Humpback Gila cypha E Freshwater Yes

Darter, Niangua Etheostoma nianguae T Freshwater Yes

Madtom, Neosho Noturus placidus T Freshwater No

Shiner, Topeka Notropis topeka (=tristis) E Freshwater Yes

Sturgeon, Gulf Acipenser oxyrinchus desotoi T Freshwater, Saltwater Yes

Sturgeon, Pallid Scaphirhynchus albus E Freshwater No

 Gastropod

Cavesnail, Tumbling Creek Antrobia culveri E Freshwater, No

Subterraneous

 Insect

Beetle, American Burying Nicrophorus americanus E Terrestrial No

Dragonfly, Hine's Emerald Somatochlora hineana E Terrestrial, Freshwater Yes

 Mammal

Bat, Gray Myotis grisescens E Terrestrial, No

Subterraneous

Bat, Indiana Myotis sodalis E Terrestrial, Yes

Subterraneous

 Monocot

Orchid, Western Prairie Fringed Platanthera praeclara T Terrestrial No

North Carolina ( 59) species: CH

 Arachnid

Spider, Spruce-fir Moss Microhexura montivaga E Terrestrial Yes

 Bird

Plover, Piping Charadrius melodus E Terrestrial Yes

Stork, Wood Mycteria americana E Terrestrial No

Tern, Roseate Sterna dougallii dougallii E Terrestrial No

Woodpecker, Red-cockaded Picoides borealis E Terrestrial No

 Bivalve

Elktoe, Appalachian Alasmidonta raveneliana E Freshwater Yes

Mussel, Dwarf Wedge Alasmidonta heterodon E Freshwater No
−14−

Mussel, Heelsplitter Carolina Lasmigona decorata E Freshwater Yes

Mussel, Oyster Epioblasma capsaeformis E Freshwater Yes

Pearlymussel, Little-wing Pegias fabula E Freshwater No

Purple Bean Villosa perpurpurea E Freshwater Yes

Spinymussel, James River Pleurobema collina E Freshwater No

Spinymussel, Tar River Elliptio steinstansana E Freshwater No

 Dicot

Amaranth, Seabeach Amaranthus pumilus T Coastal No

Avens, Spreading Geum radiatum E Terrestrial No

Bittercress, Small-anthered Cardamine micranthera E Terrestrial No

Blazing Star, Heller's Liatris helleri T Terrestrial No

Bluet, Roan Mountain Hedyotis purpurea var. montana E Terrestrial No

Chaffseed, American Schwalbea americana E Terrestrial No

Coneflower, Smooth Echinacea laevigata E Terrestrial No

Dropwort, Canby's Oxypolis canbyi E Terrestrial, Freshwater No

Goldenrod, Blue Ridge Solidago spithamaea T Terrestrial No

Harperella Ptilimnium nodosum E Freshwater No

Heartleaf, Dwarf-flowered Hexastylis naniflora T Terrestrial No

Heather, Mountain Golden Hudsonia montana T Terrestrial Yes

Joint-vetch, Sensitive Aeschynomene virginica T Terrestrial, Brackish No

Loosestrife, Rough-leaved Lysimachia asperulaefolia E Terrestrial No

Meadowrue, Cooley's Thalictrum cooleyi E Terrestrial No

Pitcher-plant, Green Sarracenia oreophila E Terrestrial, Freshwater No

Pitcher-plant, Mountain Sweet Sarracenia rubra ssp. jonesii E Terrestrial, Freshwater No

Pondberry Lindera melissifolia E Terrestrial No

Spiraea, Virginia Spiraea virginiana T Terrestrial No

Sumac, Michaux's Rhus michauxii E Terrestrial No

Sunflower, Schweinitz's Helianthus schweinitzii E Terrestrial No

 Fish

Chub, Spotfin Erimonax monachus T Freshwater Yes

Shiner, Cape Fear Notropis mekistocholas E Freshwater Yes

Silverside, Waccamaw Menidia extensa T Freshwater Yes

Sturgeon, Shortnose Acipenser brevirostrum E Freshwater, Saltwater No

 Gastropod

Snail, Noonday Mesodon clarki nantahala T Terrestrial No

 Insect

Butterfly, Saint Francis' Satyr Neonympha mitchellii francisci E Terrestrial No

 Mammal

Bat, Gray Myotis grisescens E Terrestrial, No

Subterraneous

Bat, Indiana Myotis sodalis E Terrestrial, Yes

Subterraneous
−15−

Bat, Virginia Big-eared Corynorhinus (=Plecotus) E Terrestrial, Yes

townsendii virginianus Subterraneous

Squirrel, Carolina Northern Flying Glaucomys sabrinus coloratus E Terrestrial No

Wolf, Red Canis rufus E Terrestrial No

 Marine mml

Manatee, West Indian Trichechus manatus E Saltwater Yes

Whale, Finback Balaenoptera physalus E Saltwater No

Whale, Humpback Megaptera novaeangliae E Saltwater No

Whale, North Atlantic right Eubalaena glacialis (incl. E Saltwater Yes

 Monocot

Arrowhead, Bunched Sagittaria fasciculata E Freshwater No

Irisette, White Sisyrinchium dichotomum E Terrestrial No

Pink, Swamp Helonias bullata T Terrestrial, Freshwater No

Pogonia, Small Whorled Isotria medeoloides T Terrestrial No

Sedge, Golden Carex lutea E Terrestrial No

 Reptile

Sea turtle, green Chelonia mydas E Saltwater Yes

Sea turtle, hawksbill Eretmochelys imbricata E Saltwater, Coastal Yes

Sea turtle, Kemp's ridley Lepidochelys kempii E Saltwater, Coastal No

Sea turtle, leatherback Dermochelys coriacea E Saltwater, Coastal Yes

Sea turtle, loggerhead Caretta caretta T Saltwater, Coastal No

Ohio ( 22) species: CH

 Bird

Plover, Piping Charadrius melodus E Terrestrial Yes

 Bivalve

Fanshell Cyprogenia stegaria E Freshwater No

Mucket, Pink (Pearlymussel) Lampsilis abrupta E Freshwater No

Mussel, Clubshell Pleurobema clava E Freshwater No

Pearlymussel, Purple Cat's Paw Epioblasma obliquata obliquata E Freshwater No

Pearlymussel, White Cat's Paw Epioblasma obliquata perobliqua E Freshwater No

Riffleshell, Northern Epioblasma torulosa rangiana E Freshwater No

 Dicot

Clover, Running Buffalo Trifolium stoloniferum E Terrestrial No

Daisy, Lakeside Hymenoxys herbacea T Freshwater No

Monkshood, Northern Wild Aconitum noveboracense T Terrestrial No

Spiraea, Virginia Spiraea virginiana T Terrestrial No

 Fish

Madtom, Scioto Noturus trautmani E Freshwater No

 Insect

Beetle, American Burying Nicrophorus americanus E Terrestrial No

Butterfly, Karner Blue Lycaeides melissa samuelis E Terrestrial No
−16−

Butterfly, Mitchell's Satyr Neonympha mitchellii mitchellii E Terrestrial, Perm. No

wetland

Dragonfly, Hine's Emerald Somatochlora hineana E Terrestrial, Freshwater Yes

 Mammal

Bat, Gray Myotis grisescens E Terrestrial, No

Subterraneous

Bat, Indiana Myotis sodalis E Terrestrial, Yes

Subterraneous

 Monocot

Orchid, Eastern Prairie Fringed Platanthera leucophaea T Terrestrial No

Pogonia, Small Whorled Isotria medeoloides T Terrestrial No

 Reptile

Snake, Lake Erie Water Nerodia sipedon insularum T Terrestrial, Freshwater No

Snake, Northern Copperbelly Water Nerodia erythrogaster neglecta T Terrestrial, Freshwater No

South Carolina ( 37) species: CH

 Amphibian

Salamander, Flatwoods Ambystoma cingulatum T Terrestrial, Freshwater, No

Vernal pool

 Bird

Plover, Piping Charadrius melodus E Terrestrial Yes

Stork, Wood Mycteria americana E Terrestrial No

Warbler, Bachman's Vermivora bachmanii E Terrestrial No

Woodpecker, Red-cockaded Picoides borealis E Terrestrial No

 Bivalve

Mussel, Heelsplitter Carolina Lasmigona decorata E Freshwater Yes

 Dicot

Amaranth, Seabeach Amaranthus pumilus T Coastal No

Amphianthus, Little Amphianthus pusillus T Freshwater No

Chaffseed, American Schwalbea americana E Terrestrial No

Coneflower, Smooth Echinacea laevigata E Terrestrial No

Dropwort, Canby's Oxypolis canbyi E Terrestrial, Freshwater No

Gooseberry, Miccosukee Ribes echinellum T Terrestrial No

Harperella Ptilimnium nodosum E Freshwater No

Heartleaf, Dwarf-flowered Hexastylis naniflora T Terrestrial No

Loosestrife, Rough-leaved Lysimachia asperulaefolia E Terrestrial No

Pitcher-plant, Mountain Sweet Sarracenia rubra ssp. jonesii E Terrestrial, Freshwater No

Pondberry Lindera melissifolia E Terrestrial No

Sunflower, Schweinitz's Helianthus schweinitzii E Terrestrial No

 Fish

Sturgeon, Shortnose Acipenser brevirostrum E Freshwater, Saltwater No

 Mammal

Bat, Indiana Myotis sodalis E Terrestrial, Yes

Subterraneous
−17−

Wolf, Red Canis rufus E Terrestrial No

 Marine mml

Manatee, West Indian Trichechus manatus E Saltwater Yes

Whale, Finback Balaenoptera physalus E Saltwater No

Whale, Humpback Megaptera novaeangliae E Saltwater No

Whale, North Atlantic right Eubalaena glacialis (incl. E Saltwater Yes

 Monocot

Arrowhead, Bunched Sagittaria fasciculata E Freshwater No

Irisette, White Sisyrinchium dichotomum E Terrestrial No

Pink, Swamp Helonias bullata T Terrestrial, Freshwater No

Pogonia, Small Whorled Isotria medeoloides T Terrestrial No

Trillium, Persistent Trillium persistens E Terrestrial No

Trillium, Relict Trillium reliquum E Terrestrial No

 Reptile

Sea turtle, green Chelonia mydas E Saltwater Yes

Sea turtle, hawksbill Eretmochelys imbricata E Saltwater, Coastal Yes

Sea turtle, Kemp's ridley Lepidochelys kempii E Saltwater, Coastal No

Sea turtle, leatherback Dermochelys coriacea E Saltwater, Coastal Yes

Sea turtle, loggerhead Caretta caretta T Saltwater, Coastal No

Snake, Eastern Indigo Drymarchon corais couperi T Terrestrial Yes

Tennessee ( 85) species: CH

 Arachnid

Spider, Spruce-fir Moss Microhexura montivaga E Terrestrial Yes

 Bird

Stork, Wood Mycteria americana E Terrestrial No

Tern, Interior (population) Least Sterna antillarum E Terrestrial No

Woodpecker, Red-cockaded Picoides borealis E Terrestrial No

 Bivalve

Combshell, Upland Epioblasma metastriata E Freshwater Yes

Elktoe, Appalachian Alasmidonta raveneliana E Freshwater Yes

Fanshell Cyprogenia stegaria E Freshwater No

Kidneyshell, Triangular Ptychobranchus greenii E Freshwater Yes

Mucket, Pink (Pearlymussel) Lampsilis abrupta E Freshwater No

Mussel, Alabama Moccasinshell Medionidus acutissimus T Freshwater Yes

Mussel, Clubshell Pleurobema clava E Freshwater No

Mussel, Coosa Moccasinshell Medionidus parvulus E Freshwater Yes

Mussel, Cumberland Combshell Epioblasma brevidens E Freshwater Yes

Mussel, Cumberland Elktoe Alasmidonta atropurpurea E Freshwater Yes

Mussel, Cumberland Pigtoe Pleurobema gibberum E Freshwater No

Mussel, Fine-lined Pocketbook Lampsilis altilis T Freshwater Yes

Mussel, Fine-rayed Pigtoe Fusconaia cuneolus E Freshwater No
−18−

Mussel, Ovate Clubshell Pleurobema perovatum E Freshwater Yes

Mussel, Oyster Epioblasma capsaeformis E Freshwater Yes

Mussel, Ring Pink (=Golf Stick Obovaria retusa E Freshwater No

Mussel, Rough Pigtoe Pleurobema plenum E Freshwater No

Mussel, Shiny Pigtoe Fusconaia cor E Freshwater No

Mussel, Southern Pigtoe Pleurobema georgianum E Freshwater Yes

Pearlymussel, Alabama Lamp Lampsilis virescens E Freshwater No

Pearlymussel, Appalachian Quadrula sparsa E Freshwater No

Monkeyface

Pearlymussel, Birdwing Conradilla caelata E Freshwater No

Pearlymussel, Cracking Hemistena lata E Freshwater No

Pearlymussel, Cumberland Bean Villosa trabalis E Freshwater No

Pearlymussel, Cumberland Quadrula intermedia E Freshwater No

Monkeyface

Pearlymussel, Dromedary Dromus dromas E Freshwater No

Pearlymussel, Green-blossom Epioblasma torulosa gubernaculum E Freshwater No

Pearlymussel, Little-wing Pegias fabula E Freshwater No

Pearlymussel, Orange-footed Plethobasus cooperianus E Freshwater No

Pearlymussel, Pale Lilliput Toxolasma cylindrellus E Freshwater No

Pearlymussel, Purple Cat's Paw Epioblasma obliquata obliquata E Freshwater No

Pearlymussel, Tubercled-blossom Epioblasma torulosa torulosa E Freshwater No

Pearlymussel, Turgid-blossom Epioblasma turgidula E Freshwater No

Pearlymussel, White Wartyback Plethobasus cicatricosus E Freshwater No

Pearlymussel, Yellow-blossom Epioblasma florentina florentina E Freshwater No

Purple Bean Villosa perpurpurea E Freshwater Yes

Rabbitsfoot, Rough Quadrula cylindrica strigillata E Freshwater Yes

Riffleshell, Tan Epioblasma florentina walkeri E Freshwater No

(=E. walkeri)

 Crustacean

Crayfish, Nashville Orconectes shoupi E Freshwater No

 Dicot

Aster, Ruth's Golden Pityopsis ruthii E Terrestrial No

Avens, Spreading Geum radiatum E Terrestrial No

Bladderpod, Spring Creek Lesquerella perforata E Floodplain No

Bluet, Roan Mountain Hedyotis purpurea var. montana E Terrestrial No

Chaffseed, American Schwalbea americana E Terrestrial No

Clover, Leafy Prairie Dalea foliosa E Terrestrial No

Coneflower, Tennessee Purple Echinacea tennesseensis E Terrestrial No

Goldenrod, Blue Ridge Solidago spithamaea T Terrestrial No

Ground-plum, Guthrie's Astragalus bibullatus E Terrestrial No

Pitcher-plant, Green Sarracenia oreophila E Terrestrial, Freshwater No

Potato-bean, Price's Apios priceana T Terrestrial No
−19−

Rock-cress, Braun's Arabis perstellata E. L. Braun var. E Terrestrial Yes

 ampla Rollins

Rock-cress, Small Arabis perstellata E. L. Braun var. E Terrestrial Yes

 perstellata Fernald

Rosemary, Cumberland Conradina verticillata T Terrestrial No

Sandwort, Cumberland Arenaria cumberlandensis E Terrestrial No

Skullcap, Large-flowered Scutellaria montana T Terrestrial No

Spiraea, Virginia Spiraea virginiana T Terrestrial No

 Fish

Chub, Slender Erimystax cahni T Freshwater Yes

Chub, Spotfin Erimonax monachus T Freshwater Yes

Dace, Blackside Phoxinus cumberlandensis T Freshwater No

Darter, Amber Percina antesella E Freshwater Yes

Darter, Bluemask (=jewel) Etheostoma sp. E Freshwater No

Darter, Boulder Etheostoma wapiti E Freshwater No

Darter, Duskytail Etheostoma percnurum E Freshwater No

Darter, Slackwater Etheostoma boschungi T Freshwater Yes

Darter, Snail Percina tanasi T Freshwater No

Logperch, Conasauga Percina jenkinsi E Freshwater Yes

Madtom, Pygmy Noturus stanauli E Freshwater No

Madtom, Smoky Noturus baileyi E Freshwater Yes

Madtom, Yellowfin Noturus flavipinnis T Freshwater Yes

Shiner, Blue Cyprinella caerulea T Freshwater No

Shiner, Palezone Notropis albizonatus E Freshwater No

Sturgeon, Pallid Scaphirhynchus albus E Freshwater No

 Gastropod

Marstonia, Royal (=Royal Snail) Pyrgulopsis ogmorhaphe E Terrestrial No

Riversnail, Anthony's Athearnia anthonyi E Freshwater No

Snail, Painted Snake Coiled Forest Anguispira picta T Terrestrial No

 Mammal

Bat, Gray Myotis grisescens E Terrestrial, No

Subterraneous

Bat, Indiana Myotis sodalis E Terrestrial, Yes

Subterraneous

Squirrel, Carolina Northern Flying Glaucomys sabrinus coloratus E Terrestrial No

Wolf, Red Canis rufus E Terrestrial No

 Monocot

Grass, Tennessee Yellow-eyed Xyris tennesseensis E Terrestrial No

Pogonia, Small Whorled Isotria medeoloides T Terrestrial No

Virginia ( 65) species: CH

 Amphibian

Salamander, Shenandoah Plethodon shenandoah E Terrestrial, Freshwater No
−20−

 Bird

Plover, Piping Charadrius melodus E Terrestrial Yes

Woodpecker, Red-cockaded Picoides borealis E Terrestrial No

 Bivalve

Fanshell Cyprogenia stegaria E Freshwater No

Mucket, Pink (Pearlymussel) Lampsilis abrupta E Freshwater No

Mussel, Cumberland Combshell Epioblasma brevidens E Freshwater Yes

Mussel, Cumberland Elktoe Alasmidonta atropurpurea E Freshwater Yes

Mussel, Dwarf Wedge Alasmidonta heterodon E Freshwater No

Mussel, Fine-rayed Pigtoe Fusconaia cuneolus E Freshwater No

Mussel, Oyster Epioblasma capsaeformis E Freshwater Yes

Mussel, Rough Pigtoe Pleurobema plenum E Freshwater No

Mussel, Shiny Pigtoe Fusconaia cor E Freshwater No

Pearlymussel, Appalachian Quadrula sparsa E Freshwater No

Monkeyface

Pearlymussel, Birdwing Conradilla caelata E Freshwater No

Pearlymussel, Cracking Hemistena lata E Freshwater No

Pearlymussel, Cumberland Bean Villosa trabalis E Freshwater No

Pearlymussel, Cumberland Quadrula intermedia E Freshwater No

Monkeyface

Pearlymussel, Dromedary Dromus dromas E Freshwater No

Pearlymussel, Green-blossom Epioblasma torulosa gubernaculum E Freshwater No

Pearlymussel, Little-wing Pegias fabula E Freshwater No

Purple Bean Villosa perpurpurea E Freshwater Yes

Rabbitsfoot, Rough Quadrula cylindrica strigillata E Freshwater Yes

Riffleshell, Tan Epioblasma florentina walkeri E Freshwater No

(=E. walkeri)

Spinymussel, James River Pleurobema collina E Freshwater No

 Crustacean

Isopod, Lee County Cave Lirceus usdagalun E Freshwater No

Isopod, Madison Cave Antrolana lira T Freshwater No

 Dicot

Amaranth, Seabeach Amaranthus pumilus T Coastal No

Birch, Virginia Round-leaf Betula uber T Floodplain No

Bittercress, Small-anthered Cardamine micranthera E Terrestrial No

Chaffseed, American Schwalbea americana E Terrestrial No

Coneflower, Smooth Echinacea laevigata E Terrestrial No

Harperella Ptilimnium nodosum E Freshwater No

Joint-vetch, Sensitive Aeschynomene virginica T Terrestrial, Brackish No

Mallow, Peter's Mountain Iliamna corei E Terrestrial No

Rock-cress, Shale Barren Arabis serotina E Terrestrial No

Sneezeweed, Virginia Helenium virginicum T Vernal pool No
−21−

Spiraea, Virginia Spiraea virginiana T Terrestrial No

Sumac, Michaux's Rhus michauxii E Terrestrial No

Sunflower, Schweinitz's Helianthus schweinitzii E Terrestrial No

 Fish

Chub, Slender Erimystax cahni T Freshwater Yes

Chub, Spotfin Erimonax monachus T Freshwater Yes

Dace, Blackside Phoxinus cumberlandensis T Freshwater No

Darter, Duskytail Etheostoma percnurum E Freshwater No

Logperch, Roanoke Percina rex E Freshwater No

Madtom, Yellowfin Noturus flavipinnis T Freshwater Yes

Sturgeon, Shortnose Acipenser brevirostrum E Freshwater, Saltwater No

 Gastropod

Snail, Virginia Fringed Mountain Polygyriscus virginianus E Terrestrial No

 Insect

Beetle, Northeastern Beach Tiger Cicindela dorsalis dorsalis T Terrestrial No

Butterfly, Mitchell's Satyr Neonympha mitchellii mitchellii E Terrestrial, Perm. No

wetland

 Mammal

Bat, Gray Myotis grisescens E Terrestrial, No

Subterraneous

Bat, Indiana Myotis sodalis E Terrestrial, Yes

Subterraneous

Bat, Virginia Big-eared Corynorhinus (=Plecotus) E Terrestrial, Yes

townsendii virginianus Subterraneous

Squirrel, Delmarva Peninsula Fox Sciurus niger cinereus E Terrestrial No

 Marine mml

Whale, Finback Balaenoptera physalus E Saltwater No

Whale, Humpback Megaptera novaeangliae E Saltwater No

Whale, North Atlantic right Eubalaena glacialis (incl. E Saltwater Yes

 Monocot

Bulrush, Northeastern (=Barbed Scirpus ancistrochaetus E Terrestrial, Freshwater No

Bristle)

Orchid, Eastern Prairie Fringed Platanthera leucophaea T Terrestrial No

Pink, Swamp Helonias bullata T Terrestrial, Freshwater No

Pogonia, Small Whorled Isotria medeoloides T Terrestrial No

 Reptile

Sea turtle, green Chelonia mydas E Saltwater Yes

Sea turtle, hawksbill Eretmochelys imbricata E Saltwater, Coastal Yes

Sea turtle, Kemp's ridley Lepidochelys kempii E Saltwater, Coastal No

Sea turtle, leatherback Dermochelys coriacea E Saltwater, Coastal Yes

Sea turtle, loggerhead Caretta caretta T Saltwater, Coastal No

Wisconsin ( 14) species: CH
−22−

 Bird

Crane, Whooping Grus americana E Terrestrial, Freshwater Yes

Plover, Piping Charadrius melodus E Terrestrial Yes

Warbler (=Wood), Kirtland's Dendroica kirtlandii E Terrestrial No

 Bivalve

Mussel, Winged Mapleleaf Quadrula fragosa E Freshwater No

Pearlymussel, Higgins' Eye Lampsilis higginsii E Freshwater No

 Dicot

Clover, Prairie Bush Lespedeza leptostachya T Terrestrial No

Locoweed, Fassett's Oxytropis campestris var. chartacea T Terrestrial No

Monkshood, Northern Wild Aconitum noveboracense T Terrestrial No

Thistle, Pitcher's Cirsium pitcheri T Terrestrial No

 Insect

Butterfly, Karner Blue Lycaeides melissa samuelis E Terrestrial No

Dragonfly, Hine's Emerald Somatochlora hineana E Terrestrial, Freshwater Yes

 Mammal

Lynx, Canada Lynx canadensis T Terrestrial No

 Monocot

Iris, Dwarf Lake Iris lacustris T Terrestrial No

Orchid, Eastern Prairie Fringed Platanthera leucophaea T Terrestrial No

No species were selected for exclusion.

Dispersed species included in report. 

5/11/2009 2:33:11 PM Ver. 2.10.4 Page 23 of 23
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460

OFFICE OF PREVENTION, 

PESTICIDES AND 

TOXIC SUBSTANCES

MEMORANDUM 

Chemical: gamma-cyhalothrin 

PC Code: 128807 

DP barcode: 289801, 289799, 

289797, 289794, 

289798, 288057 

DATE: March 19, 2004 

SUBJECT: Ecological risk assessment and human drinking water assessment for 

gamma-cyhalothrin use on multiple agricultural use sites and non-cropped areas. 

FROM: Iwona Maher, Chemist 

Norman Birchfield, Senior Biologist 

Pat Jennings, Risk Assessment Process Leader 

 Sid Abel, Branch Chief 

Environmental Risk Branch 1 

Environmental Fate and Effects Division (7507C) 

TO: William Sproat, Team Reviewer 

George LaRocca, Product Manager 

Insecticide Branch 

Registration Division (7505C) 

Summary

This review is supplemental to the assessment conducted for lambda-cyhalothrin in June 20021

and the potential risks for gamma-cyhalothrin are expected to be consistent with those predicted 

for lambda-cyhalothrin. Gamma-cyhalothrin is a purified form of cyhalothrin and lambdacyhalothrin pyrethroid insecticides and is proposed for use on a wide range of major and minor 

crops in the U.S. A number of studies were submitted by Dow AgroSciences in support of the 

proposed uses. The studies were not intended to provide sufficient information to assess the 

risks associated with proposed uses, but rather to show that available data submitted from other 

 1

 Section 3 request for new uses of lambda-cyhalothrin by Santhini Ramasamy, Iwona 

Maher, Pat Jennings, Sid Abel. June 12, 2002. DP barcodes D262918, D262919, D279087, 

D279088. 

−23−
−24−

gamma-cyhalothrin containing insecticides would be adequate for the more pure form of gammacyhalothrin and supplement existing data. Most of the newly submitted studies were given a 

“supplemental” rating, not meeting study guidelines adequately to fulfill data requirements, but 

were considered sufficient for their intended purpose of bridging and supplementing existing 

data. It is appropriate to consider studies and risk assessments for other gamma-cyhalothrin 

containing insecticides to evaluate the toxicity, fate, and mobility of gamma-cyhalothrin. 

A comparative risk assessment for seven pyrethroid insecticides (including lambda-cyhalothrin) 

was completed in 1993. EFED is collecting additional data from the Pyrethroid Working Group 

and reviewing available data to further evaluate the comparative risks of the seven pyrethroids. 

New data on the toxicity of pyrethroids, their ability to reach aquatic environments, and their 

behavior in aquatic environments will be useful in further assessing risks to aquatic organisms, 

especially sediment dwelling organisms. 

The greatest potential risks from proposed gamma-cyhalothrin uses are consistent with risks 

estimated for most pyrethroid insecticides. The highest estimated screening-level risks are to 

fish, aquatic invertebrates, and non-target insects. Off-target transport of gamma-cyhalothrin via 

both spray drift and erosion of soil bound insecticide is estimated to exceed levels necessary to 

kill aquatic animals in laboratory tests. Gamma-cyhalothrin has a high affinity for soil organic 

matter. Gamma-cyhalothrin is expected to quickly and strongly bind to organic material in the 

environment such as organic material in soil and sediment as well as dissolved and suspended 

organic materials in water. Binding to organic material can reduce the dissolved concentration 

of gamma-cyhalothrin reducing the availability of the material to fish and other organisms. 

Depending on the rate and magnitude of binding, dissolved phase concentrations of gammacyhalothrin may be reduced to below lethal concentrations for organisms living in the water 

column. Very limited data are available for sediment dwelling (benthic) organisms. Strong 

sediment binding is also expected to reduce exposure to benthic organisms but gammacyhalothrin is expected to be fairly persistent in sediment and sediment pore water 

concentrations could pose a significant risk to benthic organisms. 

Screening-level risk estimates for birds and mammals feeding on sprayed food items in the target 

area with relatively high gamma-cyhalothrin levels were also above levels of concern. Uses with 

higher application rates and animals consuming food items with higher residue levels (e.g. short 

grass) may consume lethal quantities of gamma-cyhalothrin or levels that have been shown to 

reduce feeding/body weight and induce head twitching behavior or other modified behaviors. 

The potential for significant chronic toxicity exists for both birds and mammals. Mammals are 

more acutely sensitive to gamma-cyhalothrin and as a result mammals, and not birds, have 

significant potential to be sensitive to acute exposures from proposed uses. 

Proposed uses for gamma-cyhalothrin include many major crops that are geographically 

distributed across the U.S. Proposed uses listed on the draft product labels (GF-231 and GF-317) 

include: 
−25−

 

· alfalfa 

· canola 

· cole crops 

· corn 

· cotton 

· fruiting vegetables 

· legume vegetables 

· lettuce 

· onion 

· peanut 

· pome fruits 

· rice 

· sorghum (grain) 

· soybean 

· stone fruits 

· sugarcane 

· sunflower 

· tobacco 

· tree nuts (including pecans) 

· wheat 

· triticale 

· conifer and deciduous trees 

(plantations, nurseries and seed 

orchards) 

· non-crop land areas adjacent to crops. 

Gamma-cyhalothrin will likely be competing in the marketplace with lambda-cyhalothrin and 

other products controlling the same target pests. The extent of its use will be a factor of its ability 

to compete with these products. Because many of the proposed crops are grown on many 

millions of acres in the U.S. and significant lambda-cyhalothrin usage has been documented on 

these crops2

, gamma-cyhalothrin has the potential to be used on many millions of acres as well. 

Thus, the treated area and the area that may be contaminated by spray drift and runoff from 

gamma-cyhalothrin use is very large. Application rates for lambda- and proposed gammacyhalothrin products are provided in Appendix A. 

Gamma- and lambda-cyhalothrin are very potent insecticides. The proposed application rates for 

gamma-cyhalothrin range from 0.0075 to 0.02 lbs active ingredient (a.i.) /acre. The low 

application rate is expected to result in very low levels of residues in the target area and lessens 

the amount of material that is available to move off-target. As a result, only organisms that are 

very sensitive to gamma-cyhalothrin are likely to have a high potential of being impacted. 

Approach to Risk Assessment

In 1999 and 2000 representatives of Dow AgroSciences presented to the Office of Pesticide 

Programs a proposed plan to bridge from existing studies of insecticides containing gammacyhalothrin (at the time known as XR-225) to the Office of Pesticide Programs in 1999 and 

2000. The Environmental Fate and Effects Division (EFED) responded to the ecotoxicity and 

environmental fate portions of the bridging plan suggesting specific studies for Dow 

AgroSciences to conduct for bridging purposes.3

 Dow AgroSciences then initiated the 

2

USDA Agricultural Chemical Usage 2002 Field Crops Summary May 2003. 

http://usda.mannlib.cornell.edu/reports/nassr/other/pcu-bb/agcs0503.pdf 

 

3

 Memo from Norman Birchfield, Environmental Fate and Effects Division to William 

Sproat, Registration Division. DP barcode D265669. 
−26−

 

environmental fate and toxicity studies using U.S. EPA study guidelines.4

 The studies were 

submitted to the Office of Pesticide Programs and reviewed by EFED using Standard Evaluation 

Procedures. The acceptability and key results of the studies were summarized in Data 

Evaluation Reports (DERs). Studies conducted according to EPA guidelines do not always 

produce results of adequate quality for risk assessment if problems occur during the study. The 

gamma-cyhalothrin studies were classified as either “acceptable/core” (meeting guideline 

requirements), “supplemental” (not meeting guideline requirement but providing some sound 

and useful information), or “invalid” (not meeting guideline requirements and not providing 

sound or useful information). 

The results of acceptable and supplemental gamma-cyhalothrin studies were compared to results 

from similar studies conducted for cyhalothrin and lambda-cyhalothrin to confirm that fate, 

persistence, and toxicity parameters between the chemicals were consistent. Two potential 

product labels for gamma-cyhalothrin were reviewed and compared to existing product labels for 

lambda-cyhalothrin to confirm that use sites, application rates, application intervals, and 

application methods were consistent between the chemicals. Because lambda- and gammacyhalothrin uses, fate, persistence, mobility, and toxicity values were consistent, a recent risk 

assessment conducted for lambda-cyhalothrin was considered adequate for identifying use 

conditions (application rate and methods) that result in exposures to non-target organisms that 

exceed levels of concern. 

EFED uses the risk quotient (RQ) method, potential exposure concentrations divided by toxicity 

levels, to identify when high-end exposures from a proposed use may result in unacceptable risks 

to non-target organisms. Risk quotients are compared to “levels of concern” to determine if the 

use assessed has the potential to cause adverse effects. A previously conducted ecological 

assessment completed in June 2002 for lambda-cyhalothrin5

 provides an adequate indication of 

the potential for gamma-cyhalothrin use to exceed levels of concern for non-target animals. 

Because the chemical and toxicological properties and use patterns are nearly identical for 

lambda- and gamma-cyhalothrin the risk quotients in the lambda-cyhalothrin assessment would 

be the same for gamma-cyhalothrin. In addition the drinking water concentrations calculated in 

the June 2002 risk assessment are expected to be reflective of gamma-cyhalothrin uses. 

The Metabolism Committee in the Health Effects Division previously opted to include ringhydroxylated lambda-cyhalothrin in the human drinking water exposure assessment. This 

degradate accounted for 12% of applied material in aerobic soil after 63 days. Exposure to the 

degradate was not considered in the ecological risk assessment because the hydroxylation of the 

gamma-cyhalothrin is expected to reduce the toxicity of the material. The hypothesized reduced 

toxicity of ring hydroxylated gamma-cyhalothrin is based on the premise that the highly 

4

http://www.epa.gov/opptsfrs/home/guidelin.htm 

5

 Section 3 request for new uses of lambda-cyhalothrin by Santhini Ramasamy, Iwona 

Maher, Pat Jennings, Sid Abel. June 12, 2002. DP barcodes D262918, D262919, D279087, 

D279088. 
−27−

 

hydrophobic nature of pyrethroid insecticides is required for their high affinity to their 

neurological receptors. Hydroxylation makes the molecule substantially more polar which 

would reduce the affinity to the receptor and thereby reduce the magnitude of neurotoxic effects. 

The precise toxicity of ring-hydroxylated gamma-cyhalothrin is uncertain. 

For the purpose of adding information to the risk characterization, open literature was evaluated 

and a spray drift exposure assessment, not included in the lambda-cyhalothrin risk assessment, 

was performed. Information on gamma-cyhalothrin’s toxicity and behavior in the environment 

was collected from the open literature,6

 summarized, and compared to registrant-submitted data. 

After review of the gamma-cyhalothrin products labels, available label parameters defining 

application conditions were used to perform a spray drift exposure analysis. 

Environmental Fate, Mobility, and Persistence

Cyhalothirn and lambda-cyhalothrin are racemic mixtures that consist of four (1R,cis,Z-S’; 

1S,cis,Z-R’; 1R, cis, Z-R’; and 1S,cis,Z-S’) and two isomers (1R,cis,Z-S’ and 1S,cis,Z-R’), 

respectively. Greater than 98% of gamma-cyhalothrin is the biologically active enantiomer 

(1R,cis,Z-S’), referred to as XDE-225 (or XR-225). 

For gamma-cyhalothrin bridging to existing environmental fate data on lambda-cyhalothrin, the 

registrant submitted a hydrolysis study (161-1, MRID 45447409), aerobic soil metabolism 

studies (162-1, MRID 45447410, 45447411), an aerobic aquatic metabolism study (162-4, 

MRID 45447412), an adsorption/desorption study (163-1, MRID 45447413), and a terrestrial 

field dissipation study (164-1, MRID 45794902). These studies were classified mostly as 

supplemental with a portion of the hydrolysis study classified as unacceptable (pH 9 and natural 

river water portion). 

An aquatic photolysis study is not available for gamma-cyhalothrin. Aquatic photolysis was a 

rapid route of lambda-cyhalothrin dissipation (half-life = 25 days) when compared to other soil, 

sediment, and water half-lives. Upon review of the registrant’s bridging plan the aqueous 

photolysis study was not requested. Because aqueous photolysis is not expected to be 

enantioselective, it is appropriate to use lambda-cyhalothrin aqueous photolysis rates for gammacyhalothrin. For this assessment it is assumed that gamma-cyhalothrin photodegradation rate is 

comparable to that of lambda-cyhalothrin. It is worth noting that aqueous photolysis is a 

relatively fast route of degradation for lambda-cyhalothrin, the relative contribution of this route 

of degradation in surface water modeling and the environment is not expected to be significant. 

Gamma-cyhalothrin’s high soil binding affinity and the limited light penetration into most water 

bodies greatly reduces the potential for aqueous photodegradation. 

Gamma-cyhalothrin appears to be immobile and moderately persistent in laboratory studies and 

in the field environment. It is highly unlikely that gamma-cyhalothrin will reach ground water 

resources due to its high soil adsorption affinity. Gamma-cyhalothrin was not detected below the 

6

Information sources included the ECOTOX data base (http://www.epa.gov/ecotox/) and 

ScienceDirect were used as sources of open literature (http://www.sciencedirect.com/). 
−28−

 

0-15 cm soil depth, with the exception of a single detection below the LOQ (0.010 μg/g) at 4 

days post-treatment in the 15-30 cm soil depth in MS site. (Pan evaporation data, however, were 

not submitted to assess whether the rainfall amount was sufficient to facilitate leaching.) The 

chemical will likely reach surface water via soil erosion and particulate runoff after rainfall, and 

via spray drift during or shortly after application. A published report measured 73% to 90% of 

synthetic pyrethroids are bound to eroding sediment in runoff.7

As for lambda-cyhalothrin, the major routes of gamma-cyhalothrin transport and dissipation are 

binding to soil particles (Kd = 239 - 826) and degradation through abiotic processes via alkaline 

hydrolysis (at pH 9.0 t1/2=2.5 days), and through biotic processes via aerobic soil metabolism 

(t1/2=28-37 days) and aerobic aquatic metabolism (t1/2=40 days in total system). 

Gamma-cyhalothrin is stable to hydrolysis in pH 5 and pH7 sterile buffer solutions. Because it is 

not certain at this time whether gamma-cyhalothrin residues degraded during storage in the pH9 

buffer solution test, the calculated half-life value of 2.53 days is highly uncertain. At pH 9 

lambda-cyhalothrin hydrolyzed with a half-life of 13 days. The aqueous and soil photolysis 

and anaerobic aquatic metabolism studies were not submitted for gamma-cyhalothrin. It can be 

assumed, however, that the chemical will behave similarly to lambda-cyhalothrin in both 

processes. During photolysis on the soil surface, only 13-16% of the applied lambda-cyhalothrin 

degraded after ca. 35 days. In water/sediment systems under anaerobic conditions lambdacyhalothrin degraded with a half-life of 113 to 142 days. It is highly likely that on soil surface 

gamma-cyhalothrin will photodegrade with a rate similar to lambda-cyhalothrin. Lambdacyhalothrin photodegraded in clear laboratory water with an average half-life of 25 days. 

Data on aerobic soil metabolism of the capsule suspension formulation was submitted in order to 

evaluate whether encapsulating would increase the persistence of gamma-cyahalothrin relative to 

the technical material. Based on the results of the capsule suspension study with gammacyhalothrin the capsule suspension formulation (CS) (GF-231, purity 14.7% a.i.) is expected to 

degrade aerobically in soil with comparable rates to the technical product. Gamma-cyhalothrin 

formulated as capsule suspension degraded in the aerobic soil with the half-lives of 33 and 52 

days. Degradation of gamma-cyhalothrin in aerobic soil appears to occur in a similar manner to 

that of cyhalothrin and lambda-cyhalothrin. The studies submitted for bridging purposes do not 

provide an indication of the soil properties that increase or decrease the rate of degradation. 

However, the degradates observed in the aerobic soil metabolism studies for lambda- and 

gamma-cyhalothrin (e.g. hydroxylated products) suggest that the type and activity of soil 

microbes could affect the rate of gamma-cyhalothrin degradation. Hydroxylation at the para-C 

of the phenoxy ring of gamma-cyhalothrin appears to yield 3-(2-chloro-3,3,3-trifluoro-1-

propenyl)-2,2-dimethylcyclopropanecarboxylic acid cyano[3-(4-hydroxyphenoxy) 

phenyl]methyl ester which then yields 3-(4-hydroxyphenoxy)-benzaldehyde and 3-phenoxybenzoic acid following ester cleavage, and loss of the cyano group. Further oxidation and 

hydrolysis reactions presumably resulted in the ultimate formation of CO2. 3-Phenoxy-benzoic 

7

 W Liu, JJ Gan, S Lee, JN Kabashima. 2004. Phase distribution of synthetic pyrethroids 

in runoff and stream water. Environmental Toxicology and Chemistry. 23(1)7-11. 
−29−

acid can also be formed following ester cleavage, loss of the cyano group and oxidation of 

gamma-cyhalothrin with further reactions ultimately forming CO2. In aerobic soil metabolism 

study of technical product gamma-cyhalothrin major degradation products were 3-(4-

hydroxyphenoxy)-benzaldehyde (the maximum concentration of 12.2% of the applied at17 days 

posttreatment) and CO2 (totaled 24.1-26.1% at 95 days posttreatment; MRID 45447411). 

After reaching natural water gamma-cyhalothrin will partition to dissolved organic material, 

suspended solids, and sediment. In the aerobic aquatic metabolism study [14C]gammacyhalothrin dissipated from the water layer very rapidly and was detected at ≤4.5% of the applied 

at any sampling interval from time zero through 30 days posttreatment. The first measurement 

of gamma-cyhalothrin in the dissolved phase on day 0 of the study was 3.7% of applied material. 

On day 14 the dissolved level had decreased to 1.8% of the applied material. In the sediment 

gamma-cyhalothrin degraded with an extrapolated half-life of 41 days. The end products appear 

to be 3-phenoxy-benzaldehyde, 3–phenoxy-benzoic acid, and 3-(2-chloro-3,3,3-trifluoro-1-

propenyl)-2,2-dimethylcyclopropane-carboxylic acid cyano[3-(4-

hydroxyphenoxy)phenyl]methyl ester. The major transformation product in the aerobic aquatic 

metabolism study was 3-phenoxybenzoic acid. In the total system the maximum concentration 

of 3-phenoxybenzoic acid was 26.9% of the applied (23.6% in water column, 3.3% in sediment) 

at 30 days posttreatment in one replicate (the last sampling interval; MRID 45447412). 

Gamma-cyhalothrin simple Kd values ranged from 239 to 826 (cyhalothrin Kd = 355-601) and 

corresponding Koc values from 34,133 to 92,692 for all tested soils (cyhalothrin Koc = 28,176 -

74,212; MRID 45447413). Just as for cyhalothrin and lambda-cyhalothrin there was no linear 

relationship between the soil organic carbon content and the Kd values for different soils for 

gamma-cyhalothrin. These data suggest that gamma-cyhalothrin sorption is not dependent on 

the soil organic matter content thus the Koc model may not be appropriate. Because Kd values 

were obtained only at one concentration the Freundlich adsorption/desorption coefficients could 

not be calculated. These data suggest that gamma-cyhalothrin, similar to cyhalothrin and 

lambda-cyhalothrin, is expected to be largely immobile in soil and water environments with 

settled sediment. The bulk of gamma-cyhalothrin transport would most likely occur with 

movement of soil as erosion in runoff and suspended sediment in lotic (moving) water bodies. 

Because the capsule suspension formulation might be expected to behave differently in the 

environment compared to non-encapsulated formulations, a terrestrial field dissipation study 

using the gamma-cyhalothrin capsule suspension (CS) was conducted. Gamma-cyhalothrin 

capsule suspension formulation, when applied to the bare ground, dissipated with half-lives of 16 

days in WA site and 30 days in CA site. Field soil samples were not analyzed for transformation 

products (164-1, MRID 45794902). The study authors stated that gamma-cyhalothrin was the 

only residue of environmental concern because the major degradates are fully and rapidly 

mineralized in soil and water, do not leach, and are formed via the detoxification process of ester 

cleavage. 

Table 1 presents the physico-chemical and environmental fate data for gamma-cyhalothrin and 

lambda-cyhalothrin. Comparison of these data indicates that lambda-cyhalothrin and gammacyhalothrin have similar degradation rates in soil and aquatic environments and affinity to soil. 
−30−

Table 1. Physico-chemical and environmental fate parameters for bridging of gamma-cyhalothrin with lambdacyhalothrin

Parameters (units) 

Gamma-cyhalothrin Lambda-cyhalothrin

Value Source of 

Info/Reference

Value Source of 

Info/Reference

Molecular Weight 449.86 449.86 

Solubility (ppm) 0.002 MRID 45447410 0.005 MRID 00151580 

Vapor Pressure (mm Hg at) 2.588 x 10-9 at 25 o

C MRID 45447409 1.5x10-9 at 20 oC Registrant data 

Henry’s Constant (atm·m3/mol) 2.181 x 10-7 MRID 45794901 2.4 x10-7 Registrant data 

Octanol-Water Partition 

Coefficient 

90698 log KOW = 4.96; 

MRID 45794902. 

log KOW = 7.0 

Soil Partition Coefficient 

(Kd in mL/g) 

672, 751, 826, 239 MRID 45447413 1,970 - 7,610 

555, 601, 630, & 

3551

MRID 44861503 

MRID 45447413 

Soil Partition Coefficient 

(Koc in mL/g) 

34133, 92692, 69952, 

41932 

MRID 45447413 110,000-724,000 

28176, 74212, 

53345, 622421

MRID 44861503 

MRID 45447413 

Hydrolysis T1/2 pH5 stable 

pH7 136 days 

pH9 2.53 days* 

river water 27 days* 

MRID 

454474092

pH5 stable 

pH7 stable 

pH9 13 days 

MRID 001516043

Aqueous Photolysis (pH 5) T1/2 n/a 25 days (avg) MRID 44861501 

Soil Photolysis T1/2 n/a stable MRID 400524053

Aerobic Soil Metabolism T1/2 28 days - sandy loam 

37 days - silt loam 

33 days - loam5

52 days - silt loam5

MRID 45447411 

MRID 45447410 

24-73 days 

12 days - loam6

15 days -silt loam6

MRIDs: 

001516073

 and 

000899954

MRID 45447410 

Aerobic aquatic metabolism 

T1/2

40.1 days - total 

system7

41 days - in sediment7

<<3 days - water col. 

MRID 45447412 21-34 days 

46 days8

MRID 44861506 

MRID 44367402 

Anaerobic aquatic 

metabolism T1/2

n/a 113-142 days MRIDs: 44367401 

and 00151607 

Field Dissipation T1/2 (days) 15.6 (r2

 = 0.85); MS 

29.5 (r2

 = 0.93); CA for 

GF-231; 14.8% a.i., CS 

MRID 45794902 12-64 days 

for PP321; EC 

MRID 40052407 

1

- these four coefficient values are for cyhalothrin, cyhalothrin was tested along gamma-cyhalothrin in the same lab study, 2

 - natural river water and pH9 T1/2 values are of high uncertainty, *- at this time these data are classified unacceptable 

upgradable, 3

 - PP321 formulation was tested, 4 - benzene ring-labeled [14C]cypermethrin was tested, 5 - XDE-225 tested as capsule suspension (CS) formulation (GF-231; purity 14.8% a.i.), the type and activity of soil microbes 

could affect the rate of gamma-cyhalothrin degradation. 6 - lambda-cyhalothrin tested as CS (Warrior T; purity 11.8%), 7 - 

extrapolated values, 8 - tested under gradient redox potential, n/a - not available.
−31−

 

Toxicity to Non-Target Organisms 

For aquatic organisms, available data suggest that gamma-cyhalothrin is most toxic to 

invertebrates such as daphnids and gammarids. Fish are also extremely sensitive to gammacyhalothrin. For terrestrial organisms, insects (and most likely other invertebrates) appear to be 

most sensitive, followed by mammals, birds and then plants. The form of the end-use product, 

including microencapsulation, does not appear to greatly alter the toxicity of gamma-cyhalothrin 

in aquatic or terrestrial toxicity studies. A more detailed summary of registrant-generated 

gamma-cyahlothrin toxicity data compared to lambda-cyhalothrin is presented in Appendix B. A 

visual inspection of mortality endpoints for lambda-cyhalothrin available in the ECOTOX 

database suggests that registrant-supplied data is consistent with values reported in the open 

literature. 

To calculate gamma-cyhalothrin toxicity levels where direct data did not exist, lambdacyhalothrin results were multiplied by the percent composition of the most active enantiomer 

(41% of 1R,cis,Z-S’)

8

 in lambda-cyhalothrin and then divided by 100. For example, a lambdacyhalothrin toxicity value of 1 g/L would be calculated as 0.41 g/L for gamma-cyhalothrin. 

When lambda-cyhalothrin toxicity data were used to calculate gamma-cyhalothrin toxicity, a 

statement to that effect is always made. 

Fish Toxicity

Acute toxicity studies performed on bluegill and rainbow trout using technical or formulated 

gamma- or lambda-cyhalothrin indicate that both of these materials are very highly toxic to 

freshwater fish. The results from acute toxicity study using sheepshead minnow indicate 

lambda-cyhalothrin is also very highly toxic to fish of estuarine/marine origin. Fifty percent of 

freshwater fish test species are expected to be killed (LC50) when exposed to gamma-cyhalothrin 

at concentrations in the 0.029 to 0.19 g/L range. Less data are available for estuarine fish but 

the lambda-cyhalothrin data was adjusted by the percent composition of the most active 

enantiomer, as described above, to calculate an LC50 of approximately 0.33 g/L for gammacyhalothrin. 

The dose-response relationship in acute fish toxicity studies with lambda- and gammacyhalothrin is steep. Toxicity slopes are in the range of 3 to 7. These high (steep) slope values 

indicates that mortality levels can increase rapidly with small increases in exposure. 

Fish chronic toxicity to lambda-cyahlothrin was also adjusted to estimate gamma-cyhalothrin 

toxicity. Based on NOAECs in fathead minnow and sheepshead minnow, freshwater fish may 

be more sensitive to toxic effects of lambda-cyhalothrin than estuarine/marine fish. The 

expected NOAEC for gamma-cyhalothrin is 0.013 g/L for freshwater fish and 0.10 g/L for 

estuarine fish. 

8

Personal communication. Jess Rowland, Health Effects Division, Office of Pesticide 

Programs. February 12, 2004 email. 
−32−

 

Aquatic Invertebrates Toxicity

In general, gamma- and lambda-cyhalothrin and their formulated products are classified as very 

highly toxic to aquatic invertebrates. Among the freshwater invertebrates, Gammarus is more 

sensitive to the test materials. Data from gamma-cyhalothrin studies suggests that neonate 

Gammarus are the most sensitive life stage with an LC50 value of 0.48 ng/L (part per trillion). 

Although this toxicity level is the lowest that the reviewer has noted for any pesticide, problems 

in the study with declining test material concentrations suggest that a more accurate LC50 value 

would be lower. 

The comparison of chronic no-observable-adverse-effect concentrations (NOAECs) reported for 

both Daphnia magna (selected as a surrogate for freshwater invertebrates) and mysid shrimp 

(selected as a surrogate for estuarine/marine invertebrates) indicates that mysid shrimp are more 

sensitive to lambda-cyhalothrin toxicity than Daphnia. A daphnid study for gamma-cyhalothrin 

was not considered adequate to determine a toxicity endpoint due to variable exposure levels and 

inadequate quantitation of the test material. Extrapolating from the data available for lambdacyhalothrin, the freshwater NOAEC for gamma-cyhalothrin is expected to be in the range of 0.82 

to 1.64 ng/L. The estuarine/marine NOAEC is expected to be 0.08 ng/L. Both the estuarine and 

freshwater NOAECs are extremely low relative to other pesticides. 

The dose-response relationship in aquatic invertebrate toxicity studies with lambda- and gammacyhalothrin is moderate. Reported probit toxicity slopes are approximately 1. A high slope 

value indicates that mortality levels can increase rapidly with small increases in exposure. 

A published report9 on gamma-cyhalothrin suggested that encapsulated formulations could 

attenuate toxicity reducing toxicity to invertebrates by factors of 10 to 63. The two proposed 

formulations of gamma-cyhalothrin are both microencapsulated. Submitted studies with 

encapsulated formulations, however, showed no significant effect on toxicity. The effect of 

formulation type on toxicity to fish or invertebrates was considered negligible. 

A sediment toxicity study, requested in the response to Dow AgroSciences’ bridging 

proposal and the June 2002 lambda-cyhalothrin risk assessment, was not submitted. 

Given the high toxicity to invertebrates, toxicity to benthic invertebrates is also expected. 

Avian Toxicity

Gamma and lambda-cyhalothrin are considered to be slightly toxic or practically non-toxic to 

waterfowl and upland game birds with acute or subacute exposures. Sublethal effects for 

gamma-cyhalothrin exposure were noted at the lowest test concentrations in some studies. 

Sublethal effects occurred at <480 mg gamma-cyhalothrin/kg body weight (bw) and included 

head twitching and decreased food consumption and weight gain. Results from a lambda9

 Fredicksen, HK, HG Kristensen, M Pedersen. 2003. Solid lipid microparticle 

formulations of the pyrethroid gamma-cyhalothrin - incompatibility of the lipid and the 

pyrethroid and biological properties of the formulations. Journal of Controlled Release. 86: 243-

252. 
−33−

 

cyhalothrin mallard duck reproduction study indicated that eggs laid, eggs set, eggs cracked, 

viable embryos, live embryos, normal hatchlings and 14-day old survivors were not affected at 

levels up to 30ppm. There is no reproduction study available for lambda-cyhalothrin on 

bobwhite quail and no reproductive study on any avian species for gamma-cyhalothrin. 

Mammalian Toxicity

The following studies were conducted with gamma-cyhalothrin: six acute toxicity studies, a 28-

day dietary toxicity study in rats, a 90-day dietary toxicity study in rats, a developmental toxicity 

study in rats and a complete battery of genotoxicity studies. Summaries of the gammacyhalothrin studies that are normally used in ecological risk assessment are presented below. 

Rat Acute Oral Toxicity

The acute oral LD50 was >50 mg/kg bw in males and 55 mg/kg bw in females. The acute oral 

toxicity was also evaluated in the rat for cyhalothrin and lambda-cyhalothrin in similar studies. 

The acute oral LD50 for cyhalothrin was 166 mg/kg bw, males and 144 mg/kg bw, females and 

for lambda-cyhalothrin, 79 mg/kg bw, males and 56 mg/kg bw, females. 

Summary of Rat Short Term Toxicity

Clinical signs characteristic of pyrethroid toxicity were seen for gamma-cyhalothrin (≥125 ppm) 

and cyhalothrin (≥250 ppm) in the 28-day studies. They also occurred at 100 ppm gammacyhalothrin in the 90-day study. Decreased body weight gain was a consistent effect at high dose 

level in the 28-day and 90-day studies as was reduced food consumption. 

A published study suggested that seven daily exposures of cyhalothrin at 3 to 7 mg/kg/day 

(equivalent to ~0.75 to ~1.75 mg gamma-cyhalothrin/kg/day) resulted in a number of sublethal 

effects such as intoxication, reduced locomotor activity, increased immobility, and reduced time 

spent in social interactions.10 

Non-Target Insect/Arachnid Toxicity

Gamma- and lambda-cyhalothrin as well as their formulated products are highly toxic to honey 

bees in the acute contact as well as oral toxicity studies. For contact toxicity, approximately 6 

nanograms are required to kill 50% of treated bees. For oral exposure, approximately 0.4 

micrograms are required to kill 50% of exposed bees. 

A study conducted on honey bees suggested ergosterol biosynthesis-inhibiting fungicides can 

synergize lambda-cyhalothrin toxicity.11 Simultaneous treatment of honey bees with prochloraz 

10 D Abbud Righi, J Palermo-Neto. 2003. Behavioral effects of type II pyrethroid 

cyhalothrin in rats. Toxicology and Applied Pharmacology. 191:167-176. 

11 ED Pilling, KAC Bromley-Challenor, CH Walker, PC Jepson. 1995. Mechanism of 

synergism between the pyrethroid insecticide lambda-cyhalothrin and the imidazole fungicide 

prochloraz, in the honeybee (Apis mellifera L.). Pesticide Biochemistry and Physiology. 51:1-

11. 
−34−

 

fungicide and lambda-cyhalothrin blocked metabolism of lambda-cyhalothrin effectively 

delaying the detoxification of the insecticide. 

A study conducted on the parasitic wasp Aphidius ervi, which is used as a biological pest control 

agent, showed that the wasp may be killed when contacting treated surfaces.12 Field application 

rates of lambda-cyhalothrin deposited on glass exceeded the LD50 value for the wasp by >15-

fold. 

A study conducted with Wolf spiders (Pardosa sp.) showed male spiders to be more sensitive 

than female spiders. A spray rate of 0.036 lbs lambda-cyhalothrin/acre killed 50% of male 

spiders and 19% of female spiders.13 

Aquatic Plant Toxicity

There is no study reported testing the effects of gamma- or lambda-cyhalothrin on aquatic 

vascular plants. Also no studies are reported on non-vascular plants of estuarine/marine origin 

(e.g., marine diatoms). The 50% effect level on algae growth is likely above the solubility limit. 

The NOAEC could not determined due to the shallow dose-response slope. 

Comparison of Cyhalothrin, Lambda-Cyhalothrin, and Gamma-Cyhalothrin

The pyrethroid insecticides cyhalothrin and lambda-cyhalothrin contain gamma-cyhalothrin as 

the most active chemical component. Lambda-cyhalothrin is presently used as an insecticide on 

many crops and some non-crop sites in the United States. Cyhalothrin and lambda-cyhalothrin 

contain approximately 21% and 42% of the most biologically active enantiomer (1R,cis,Z-S’)

which comprises 98% of technical gamma-cyhalothrin, respectively14. The toxicity of lambdacyhalothrin to insects and other animals is generally related to its gamma-cyhalothrin content 

(Appendix B). As a result the proposed application rates for gamma-cyhalothrin products are 

very similar to those allowed for lambda-cyhalothrin when they are adjusted for the amount of 

gamma-cyhalothrin contained in the lambda products. The maximum allowable application rates 

on proposed gamma-cyhalothrin products are half the lambda-cyhalothrin rates (Appendix A). 

The technical forms of gamma- and lambda-cyhalothrin have very similar chemical and physical 

properties and, as a result, they are expected to show very similar levels of mobility and 

persistence in the environment. Because the proposed gamma-cyhalothrin application sites and 

methods are very similar to those allowed for lambda-cyhalothrin, and the chemical properties of 

12N Desneux, H. Rafalimanana, L Kaiser. 2004. Dose-response relationship in lethal and 

behavioral effects of different insecticides on the parasitic wasp Aphidius ervi. Chemosphere. 

54:619-627. 

13 A Hof, D Heimann, J Rombke. 1995. Further development for testing the effects of 

pesticides on wolf spiders. Ecotoxicology and Environmental Safety. 31:264-270. 

14 Personal communication. Jess Rowland, Health Effects Division, Office of Pesticide 

Programs. February 12, 2004 email. 
−35−

 

gamma- and lambda-cyhalothrin are very similar, the potential exposure levels for each are also 

expected to be very similar. Since lambda-cyhalothrin is basically 42% gamma-cyhalothrin, the 

proposed uses are essentially the same as existing uses with the exception that much less of the 

insecticidally inactive isomers would be applied. 

In addition to the use patterns, the physical, chemical and toxicological properties of gammacyhalothrin are essentially the same a lambda-cyhalothrin. Both gamma- and lambdacyhalothrin are very highly toxic to fish, aquatic invertebrates, and bees; toxicity to mammals is 

lower; and birds appear to be generally less sensitive than mammals. For acute exposure to 

mammals the gamma- and lambda-cyhalothrin are both rated as Toxicity Category II. For birds 

the acute toxicity is generally higher than the limit dose. 

Overall, the fate data for both gamma- and lambda-cyhalothrin are similar. In the environment 

both lambda- and gamma-cyhalothrin show moderate persistence with water and soil half lives 

generally ranging from 2 weeks to 2 months. Gamma- and lambda-cyhalothrin both have very 

high affinity for soil. Partition coefficients for soil organic content (Koc) is almost always greater 

than 30,000. Gamma-cyhalothrin, similar to lambda-cyhalothrin, is likely to reach water bodies 

through runoff bound to soil particles and through spray drift during application. In the aquatic 

environment gamma-cyhalothrin will subsequently partition to sediments. 

Surface water concentrations for lambda-cyhalothrin ecological and drinking water exposure 

assessments in the June 2002 assessment were calculated using the PE3 shell for the Pesticide 

Root Zone Model (PRZM version 3.12) and Exposure Analysis Modeling System (EXAMS 

version 2.98).15 Since the lambda-cyhalothrin assessment was conducted, EFED has improved 

the PE3 shell (now PE4) to better account for water body temperature and flow into and out of 

the water bodies. The estimated exposure values using PE4 would likely result in slightly 

different concentration values but the differences would not be significant. 

It is concluded that, after adjusting for the amount of gamma-cyhalothrin in lambda-cyhalothrin, 

the risk quotients, drinking water estimates, and characterization from lambda-cyhalothrin 

assessment will be the same for gamma-cyhalothrin. 

Potential Acute Risks to Aquatic Organisms in the Water Column from Spray Drift

Aquatic organisms appear to have the highest potential risks from proposed gamma-cyhalothrin 

uses, predominately due to their high sensitivity to the chemical. Current labels for lambdacyhalothrin products and the proposed labels for gamma-cyhalothrin products require applicators 

to use buffer zones in proximity to aquatic areas such as “...lakes; reservoirs, rivers; permanent 

streams, marshes, potholes, or natural ponds; estuaries; and commercial fish ponds.” The 

required buffer zones are 25 feet for ground applications, 150 feet for aerial applications, and 

450 for aerial applications employing a very fine spray (following ASAE Standard -572 for 

droplet size) or using ultra low volume (a volume-per-acre definition of ultra low volume was 

not provided). Spray drift modeling was used to perform a preliminary evaluation of the size of 

15 http://www.epa.gov/oppefed1/models/water/index.htm 
−36−

 to 

, 

ft 

y with 

. 

 

buffer zones needed to reduce risks to organisms in the water column. A separate evaluation is 

necessary to better characterize risks to sediment dwelling organisms. In a more refined spray 

drift assessment a more rigorous evaluation of the variability and uncertainty of toxicity values, 

parameters affecting the freely dissolved portion of gamma-cyhalothrin, and application 

parameters would be appropriate. 

The AgDRIFT model16 (version 2.01) was used to estimate downwind deposition levels 

expected from gamma-cyhalothrin applications conducted according to label directions. In 

addition to the specified buffer zones, proposed gamma-cyhalothrin labels require applications

be made in wind speeds less than 15 mph, not to be made during temperature inversions, and

for aerial applications, to be made with a boom width of less than 75% of the wingspan. 

Temperature inversions and wider boom widths are commonly understood to increase spray dri

potential. The model assumes that applications are made directly upwind of the water bod

no downwind obstructions

For aerial applications the AgDRIFT model was run using label restrictions as inputs to estimate 

downwind distances at which concentrations in a six foot deep water body would exceed 

laboratory toxicity levels for gamma-cyhalothrin. A relatively high drift exposure scenario using 

a very fine spray (ASAE S-572), 15 mph wind, 0.04 lbs active ingredient/acre application rate, 

and standard AgDRIFT default inputs was used to represent a reasonably high-end drift event. A 

relatively low drift scenario modeled a medium spray (ASAE S-572), 3 mph wind, 0.0075 lbs 

active ingredient/acre application rate, and standard AgDRIFT default inputs. AgDRIFT inputs 

for both scenarios are included in Appendix C. 

For ground boom applications, the high boom (4 feet above the ground) and ASAE very fine to 

fine spray (actually most representative of a fine spray) were selected in 90th percentile mode 

with 0.04 lbs active ingredient/acre to represent a reasonable high-end drift event. The low boom 

16 Bilanin A J, Teske M E, Barry J W, Ekblad R B. 1989. AGDISP: The aircraft spray dispersion 

model, code development and experimental validation. Trans ASAE 32:327-334. 

Birchfield N B, Farrar D F. 1999a. Background Document for the Scientific Advisory Panel on Ground 

Hydraulic Applications: Downwind Deposition Tolerance Bounds for Ground Hydraulic Boom Sprayers. 

Environmental Fate and Effects Division, Office of Pesticide Programs, US Environmental Protection 

Agency, Washington DC 20460. http://www.epa.gov/oscpmont/sap/1999/july/boom.pdf 

Birchfield N B, Farrar D F. 1999b. Background Document for the Scientific Advisory Panel on Orchard 

Airblast: Downwind Deposition Tolerance Bounds for Orchards. Environmental Fate and Effects Division, 

Office of Pesticide Programs, US Environmental Protection Agency, Washington DC 20460. 

http://www.epa.gov/oscpmont/sap/1999/july/airblast.pdf

Bird S L, Perry S G, Ray S L, Teske M L. 2002. Evaluation of the AGDISP aerial spray algorithms in the 

AgDRIFT model. Environmental Toxicology and Chemistry 21(3):672-681. 

Hewitt A J, Johnson D R, Fish J D, Hermansky C G, Valcore D L. 2002. Development of the Spray Drift 

Task Force Database for aerial applications. Environmental Toxicology and Chemistry 21(3):648-658. 

Teske M E, Bird S L, Esterly D M, Ray S L, Perry S G. 2001. A User’s Guide for AgDRIFT 2.01: A Tiered 

Approach for the Assessment of Spray Drift of Pesticides. Continuum Dynamics Inc. Report No. 01-02. 

Teske M E, Bird S L, Esterly D M, Curbishly T B, Ray S L, Perry S G. 2002. AgDRIFT: A model for 

estimating near-field spray drift from aerial applications. Environmental Toxicology and Chemistry

21(3):659-671.
−37−

 

(2 feet above the ground) and ASAE fine to medium/coarse spray were selected in 50th percentile 

mode with 0.0075 lbs active ingredient/acre to represent a relatively low-end drift exposure 

event. AgDRIFT inputs for both scenarios are included in Appendix C. 

For airblast applications, the “sparse” option was selected with an application rate of 0.12 lbs 

active ingredient (3 times the maximum label airblast application rate of 0.04 lbs/acre17) to 

estimate a 95th percentile value for a relatively high drift scenario. The downwind deposition 

calculated with the “sparse” option corresponds to deposition observed in dormant orchard 

treatments in Spray Drift Task Force field trials (see references for AgDRIFT) and resulted in 

some of the highest orchard airblast spray drift values. The “normal” option was selected with 

an application rate of 0.0075 lbs active ingredient/acre to represent a relatively low level drift 

event. The downwind deposition calculated with the “normal” option corresponds to spray drift 

deposition observed in foliated orchards with medium canopy density in Spray Drift Task Force 

field trials. Airblast treatments of medium canopy density trees resulted in some of the lowest 

orchard airblast spray drift values. AgDRIFT inputs for both scenarios are included in Appendix 

C. 

The binding of gamma-cyhalothrin to sediment is expected to affect the magnitude and duration 

of toxicity the material in the water column. The level of toxicity to Daphnia and carp resulting 

from lambda-cyhalothrin deposited onto a test vessel was reduced by 3- to 4-fold and 7- to 40-

fold for test vessels with settled sediment and suspended sediment, respectively.18 The effects of 

gamma-cyhalothrin’s high affinity to suspended and other sediment was factored into the current 

spray drift assessment. 

The rate at which a material deposited on the surface of a water body will bind to sediments is 

determined by two processes 1) the rate of transport from the surface to the sediment and 2) the 

rate of sorption (transfer from water to solid).19 The rate at which gamma-cyhalothrin will be 

transported from the surface to suspended and settled sediment depends on the mixing rate of the 

water body. Flowing water and water bodies exposed to wind would be expected to have more 

turbulence which would distribute the chemical compared to a more static water bodies. For 

hydrophobic chemicals, like gamma-cyhalothrin, the rate of transfer from water to solid is 

17 Multiplying the application rate input into the model has the same effect as multiplying 

the downwind deposition level. Multiplying the spray drift deposition by three approximates the 

95th percentile deposition value calculated from Spray Drift Task Force data and presented to the 

FIFRA Scientific Advisory Panel in 1999. 

18 SJ Maund, MJ Hamer, JS Warinton, TJ Kedwards. 1998. Paquatic ecotoxicology of 

the pyrethroid insecticide lambda-cyhalothrin: Considerations for higher-tier aquatic risk 

assessment. Pesticide Science. 54:408-417. 

19 WJ Doucette. 2000. Soil and Sediment Sorption Coefficients. In RS Boethling and D 

Mackay (eds.) Handbook of Property Estimation Methods for Chemicals: Environmental and 

Health Sciences. CRC Press. Boca Raton, FL. 
−38−

 

expected to be rapid for a few minutes followed by a slower rate of binding over a period of 

hours and days.20 For convenience, in laboratory batch equilibrium studies 24 hours is normally 

considered to be an adequate time to reach equilibrium, or near equilibrium, concentrations. At 

equilibrium the amount of material binding to sediment over time is equal to the amount of 

material desorbing from the sediment. In the spray drift assessment, 99% of deposited material 

was assumed to be unavailable after 24 hours. The 99% value is supported by reports with 

lambda-cyhalothrin and other synthetic pyrethroids showing freely dissolved insecticide in 

stream water was only 0.4% to 1.0% of insecticide in the system21 and less than 1% applied 

material in a sediment-water system.22 

Because gamma-cyhalothrin in the environment is expected to strongly bind to dissolved organic 

material and particulates, freely dissolved concentrations in water bodies are expected to 

decrease soon after the drift event. Gamma-cyhalothrin deposited onto a water body is expected 

to initially dissolve into the water column. After entering the water column the initial 

concentration is expected to decrease until equilibrium is reached. Gamma-cyhalothrin binding 

has two effects on risk to organisms in the water column 1) the length of exposure to peak 

concentrations is expected to be on the order of hours 2) more constant exposure levels occurring 

after equilibration are expected to be substantially lower than initial peak concentrations. 

To assess the potential effect of gamma-cyhalothrin binding on effects to aquatic organisms, 

buffer zones necessary to avoid 50% mortality in three different binding/exposure scenarios were 

calculated. The first scenario assumes no gamma-cyhalothrin binds over a 96 hour period. This 

scenario represents a water body containing very little sediment and organic material, and would 

maintain the highest levels of dissolved gamma-cyhalothrin. The second scenario examines the 

effect of a very short exposure to peak gamma-cyhalothrin levels. This scenario assumes that the 

gamma-cyhalothrin deposited onto the water body will bind to sediment over a period of hours 

and become unavailable to the organisms in the water column. The third scenario examines the 

effect of expected equilibrium levels of gamma-cyhalothrin on aquatic organisms. 

In the standard pond scenario the majority of binding would likely occur over hours, exposing 

organisms to a declining gradient of gamma-cyhalothrin concentrations instead of a single steady 

state concentration. In scenario 2, an estimate of the average concentration in the water body 

during the equilibration phase is calculated by averaging the initial evenly mixed concentration 

20 SW Karickhoff. 1980. Sorption kinetics of hydrophobic pollutants in natural 

sediments. p193-205. In RA Baker (ed.) Contaminants and Sediments, Vol. 2. Ann Arbor Sci. 

Publ., Ann Arbor, MI. 

21 W Liu, JJ Gan, S Lee, JN Kabashima. 2004. Phase distribution of synthetic 

pyrethroids in runoff and stream water. Environmental Toxicology and Chemistry. 23(1)7-11. 

22 MJ Hamer, UM Goggin, K Muller, SJ Maund. 1999. Bioavailability of lambdacyhalothrin to Chironomous riparius in sediment-water and water-only systems. Aquatic 

Ecosystem Health and Management. 2:403-412. 
−39−

with no binding and the equilibrium concentration (estimated at 1% of the initial concentration). 

Since binding is expected to occur more rapidly in the beginning of the equilibration period, 

using a simple average is likely to overestimate the concentrations relative to a time-weighted 

average. 

The gamma-cyhalothrin 50% mortality level (LC50) at 24 hours is compared to the exposure 

during the 24 hour equilibration period and the LC50 at 96 hours is compared to the exposure 

estimated during the post-24 hour equilibration period. Using the 24 hour LC50 accounts for the 

expected lower toxicity during shorter exposure periods. Gamma-cyhalothrin toxicity values 

were selected from submitted bridging studies to represent toxicity to fish and aquatic 

invertebrates in the wild. 

In all exposure scenarios, gamma-cyhalothrin is assumed to evenly mix through the water 

column. The water column depth was set to 6 feet, consistent with the standard pond scenario 

used in the June 2002 lambda-cyhalothrin assessment. Shallower water bodies would result in 

less dilution and consequently higher concentrations. 

Results of the assessment are shown in Table 2. 
−40−

Table 2. Buffer zones (ft) required to reduce spray drift deposition onto water bodies to the 50% leth

Application method 

Exposure scenario 

Invertebrates1 Fish2

Low organic content water body3

Water body with suspended sediment (exposure during 24 h equilibration)4

Water body with suspended sediment (exposure after 24 h equilibrium)5

Low organic content water body3

Water body with suspended sediment (exposure during 24 h equilibratio

Aerial high >5200 >5200 80 3800 1700 

low 2800 2000 0 520 130 

Ground boom high 780 330 0 100 30 

low 0 0 0 0 0 

Airblast high 280 150 0 80 50 

low 0 0 0 0 0 

1 The toxicity levels for aquatic invertebrates, 0.011 g/L and 0.00385 g/L, were the 24 hour and 96 hour LC50 values for juvenile 

pseudolimnaeus (concentration necessary to kill 50% of the test animals). The 24 hour value was calculated by linearly interpolating b

g/L) and 85% (0.0219 g/L) 24 hour mortality values. MRID 46065601.

2 The toxicity levels for fish, 0.056 g/L and 0.029 g/L, were the 24 and 96 hour LC50 for bluegill sunfish (concentration necessary to 

The 24 hour value was calculated by linearly interpolating between 10% (0.0381 g/L) and 60% (0.0603 g/L) 24 hour mortality valu

3 Assumes all gamma-cyhalothrin depositing on the water body is dissolved and available to aquatic animals. The resulting exposure c

compared to the 96 hour toxicity values for fish and invertebrates. 

4 The exposure during the 24 hour equilibration period was assumed to be 50% of the applied material: the average of the instantaneou

applied material in the dissolved phase) and the equilibrium concentration (1% of deposited material in the dissolved phase). Because tis expected to be higher, this concentration is likely conservative. The 24 hour LC50 values were compared to exposure values to calcu

hour equilibration scenario. 

5 Assumes 99% of gamma-cyhalothrin depositing on the water body is bound, or otherwise not bioavailable. The 96 hour LC50 values w

exposure values to calculate buffer zones for the post-24 hour equilibrium scenario. 
−41−

The spray drift assessment suggests that rapid binding of gamma-cyhalothrin to suspended 

sediment or other matter could be an important aspect to consider in assessing acute aquatic 

toxicity to spray drift. When bioavailability of spray drift is reduced by 99% the current buffer 

zones provide adequate protection of aquatic organisms. In the absence of removal via binding, 

buffer zones well in excess of those on proposed labels would be required in order to protect 

aquatic species. Further information on the short-term toxicity of gamma-cyhalothrin and the 

concentration gradient over 24 hours could be used to improve the confidence of the exposure 

and toxicity values used in the current spray drift assessment. 

Risk Relative to Levels of Concern 

The conclusions of the June 2002 risk assessment for lambda-cyhalothrin accurately describe the 

potential risks from proposed gamma-cyhalothrin uses. Many acute, chronic, restricted use, and 

endangered species levels of concern are exceeded. Because the slope of gamma-cyhalothrin’s 

dose-effect relationship is moderate to steep for aquatic organisms, small increases in exposure, 

increasing risk quotients above levels of concern, have the potential to result in a high proportion 

of mortality. The risk quotients are based on studies using the technical material. Available 

tests with formulated product suggest that end use products are not significantly more toxic than 

the technical material. 

Risk quotients in the previous assessment suggest that all acute levels of concern will be 

exceeded for fish and aquatic invertebrates by the proposed gamma-cyhalothrin uses. The 

proposed uses are also expected to exceed the chronic level of concern for aquatic invertebrates. 

Most uses exceeded acute and chronic levels of concern for both insectivorous and herbivorous 

mammalian species. The uses with the lowest seasonal application rate (e.g. wheat) do not 

exceed the mammalian chronic level of concern. 

Although the toxicity of gamma-cyhalothrin is relatively low to avian species, the uses with a 

high number of repeat applications (i.e. fruiting vegetables, conifers and deciduous trees) exceed 

chronic risk levels of concern to birds feeding on lower and higher residue food items. Uses with 

lower seasonal application rates exceed levels of concern only on avian food items with higher 

residue levels. 

The proposed uses exceed acute endangered species levels of concern for aquatic invertebrates, 

fish, and mammals. Chronic endangered species levels of concern are exceeded for aquatic 

invertebrates, fish, birds (high rate uses), mammals (high rate uses). Sublethal effects to birds 

(e.g. head twitching) and mammals (e.g. decreased locomotor activity) suggest some potential 

for gamma-cyhalothrin to impact species through behavioral changes. Also the potential for 

indirect effects to endangered species exists for those species feeding on species that may be 

directly affected by gamma-cyhalothrin. Endangered species preying on aquatic invertebrates, 

fish, mammals, or birds could have lowered food abundance. 

 
Α−1 

Appendix A.

Comparison of Application Rates of Selected Lambda- and Gamma-Cyhalothrin Containing Produc

(lbs active ingredient/acre)

Target Crop 

Existing Lambda-Cyhalothrin containing products Proposed Gamma-Cyhalothrin conta

products 

Karate with Zeon 

Technology (capsule 

suspension) EPA Reg 

No. 100-1097 

Karate (emulsifiable 

concentrate) EPA Reg 

No. 100-998 

Warrior Insecticide 

with Zeon 

Technology (capsule 

suspension) EPA 

Reg. No. 100-1112 

GF-317 proposed 

label 

(microencapsulated) 

GF-231 pro

label 

(liquid formu

not specif

per 

application 

per 

season 

per 

application 

per 

season 

per 

application 

per 

season 

per 

application 

per 

season 

per 

application 

Alfalfa 0.03 0.12 0.015 0.06 0.015 Cole Crops 0.03 0.24 0.015 0.12 0.015 Canola 0.03 0.09 0.015 0.045 Corn (at plant) 

0.09 0.48 0.045 0.24 

Corn (foliar) 0.03 0.48 0.015 0.24 0.015 Cotton 0.04 0.2 0.04 0.2 0.04 0.2 0.02 0.1 0.02 Fruiting Vegetables 

0.03 0.36 0.15 0.18 0.15 

Legumes 0.03 0.12 0.015 0.06 0.015 Lettuce 0.03 0.3 0.015 0.15 0.015 Onion 0.03 0.24 0.15 
Α−2 

Comparison of Application Rates of Selected Lambda- and Gamma-Cyhalothrin Containing Produc

(lbs active ingredient/acre)

Target Crop 

Existing Lambda-Cyhalothrin containing products Proposed Gamma-Cyhalothrin conta

products 

Karate with Zeon 

Technology (capsule 

suspension) EPA Reg 

No. 100-1097 

Karate (emulsifiable 

concentrate) EPA Reg 

No. 100-998 

Warrior Insecticide 

with Zeon 

Technology (capsule 

suspension) EPA 

Reg. No. 100-1112 

GF-317 proposed 

label 

(microencapsulated) 

GF-231 pro

label 

(liquid formu

not specif

per 

application 

per 

season 

per 

application 

per 

season 

per 

application 

per 

season 

per 

application 

per 

season 

per 

application 

Peanuts 0.03 0.12 0.03 0.12 0.015 0.06 0.015 Pome Fruit 0.04 0.2 0.02 0.1 Rice 0.04 0.12 0.04 0.12 0.02 0.06 0.02 Sorghum 0.03 0.08 0.03 0.08 0.015 0.04 0.015 Soybeans 0.03 0.06 0.015 0.03 0.015 Stone Fruit 0.04 0.2 0.02 0.1 Sugarcane 0.04 0.16 0.04 0.16 0.02 0.08 0.017 Sunflower 0.03 0.12 0.015 0.06 0.015 Tobacco 0.03 0.09 0.015 0.045 Tree Nuts 0.04 0.16 0.02 0.08 Trees (conifer and deciduous) 

0.04 0.5 0.02 0.25 
Α−3 

Comparison of Application Rates of Selected Lambda- and Gamma-Cyhalothrin Containing Produc

(lbs active ingredient/acre)

Target Crop 

Existing Lambda-Cyhalothrin containing products Proposed Gamma-Cyhalothrin conta

products 

Karate with Zeon 

Technology (capsule 

suspension) EPA Reg 

No. 100-1097 

Karate (emulsifiable 

concentrate) EPA Reg 

No. 100-998 

Warrior Insecticide 

with Zeon 

Technology (capsule 

suspension) EPA 

Reg. No. 100-1112 

GF-317 proposed 

label 

(microencapsulated) 

GF-231 pro

label 

(liquid formu

not specif

per 

application 

per 

season 

per 

application 

per 

season 

per 

application 

per 

season 

per 

application 

per 

season 

per 

application 

Wheat 0.03 0.06 0.015 0.03 0.015 

Appendix B.Toxicity to Non-Target Organisms For aquatic organisms, available toxicity data suggests that gamma-cyhalothrin is most to invertebrates such as dgammarids. Fish are also extremely sensitive to gamma-cyhalothrin. For terrestrial organisms, insects (and mosinvertebrates) appear to be most sensitive, followed by mammals, birds and then plants. Fish ToxicityAcute toxicity studies performed in bluegill and rainbow trout using technical or formulated gamma or lambda-cthat both of these materials are very highly toxic to freshwater fish. The results from acute toxicity study using s

also indicate lambda-cyhalothrin is very highly toxic to fish of estuarine/marine origin. The results of acute toxic

in freshwater and estuarine/marine fish are summarized in Table A1. 

Table A1. Acute toxic effects of gamma and lambda-cyhalothrin in on freshwater and estuarine fish
Α−4 

Species Study 

Guideline 

A.I. % 

A.I. 

Toxicity Endpoint (95 % Confidence Interval) μg a.i. /L 

Toxicity Classification 

Study Classification 

MRID # 

Freshwater FishBluegill Sunfish (Lepomis macrochirus)

72-1a lambdacyhalothri

n 

98 LC50 96 hr: 0.210 

(0.16-0.31) NOAEC : 0.16 (mortality) 

very highly toxic 

Core 151598 

99 LC50 96 hr: 0.106 

(0.086-0.140) NOAEC : 0.034 (mortality) 

very highly toxic 

Supplemental 

45447216 

gammacyhalothrin 

100 LC50 96 hr: 0.051 

(0.039-0.066) NOAEC : <0.013 (mortality and sublethal) 

very highly toxic 

Supplemental 

45447216 

100 LC50 96 hr: 0.029 

(0.021-0.039) NOAEC : 0.02 (mortality) NOAEC : 0.0077 (sublethal effects) 

very highly toxic 

Supplemental 

45447215 

Bluegill Sunfish (Lepomis macrochirus)

72-1b lambdacyhalothri

n 

12.9 LC50 96 hr : 2.2 

(1.9-2.7) NOAEC : 0.77 

very highly toxic 

Core 151601 

24 LC50 96 hr : 1.2 

(1.0-1.5) NOAEC :0.46 

very highly toxic 

Core 4390881

2 
Α−5 

Table A1. Acute toxic effects of gamma and lambda-cyhalothrin in on freshwater and estuarine fishSpecies Study 

Guideline 

A.I. % 

A.I. 

Toxicity Endpoint (95 % Confidence Interval) μg a.i. /L 

Toxicity Classification 

Study Classification 

MRID # 

Rainbow Trout (Oncorhynchus mykiss)

72-1c lambdacyhalothri

n 

98 LC50 96 hr: 0.240 

(0.20-0.29) NOAEC : 0.11 (mortality) 

very highly toxic 

Core 151597 

99 LC50 96 hr: 0.19 

(0.16-0.38) NOAEC : 0.051 (sublethal effects) 

very highly toxic 

Supplemental 

454472 

gammacyhalothrin 

100 LC50 96 hr: 0.19 

(0.16-0.22) NOAEC : 0.031 (sublethal effects) 

very highly toxic 

Supplemental 

45447217 

100 LC50 96 hr: 0.072 

(0.057-0.091) NOAEC: <0.0093 (mortality and sublethal effects) 

very highly toxic 

Supplemental 

45447214 

14.7 LC50 96 hr: 1.10 

(0.86-1.89) NOAEC: 0.28 (mortality and sublethal effects) 

very highly toxic 

Core 4544721

8 

Rainbow Trout (Salmo gairdneri)

72-1d lambdacyhalothri

n 

12.9 LC50 96 hr : 3.4 

NOAEC : N/A 

very highly toxic 

Core 151600 

Rainbow Trout 24 LC50 96 hr : 2.7 very highly Core 4390881
Α−6 

Table A1. Acute toxic effects of gamma and lambda-cyhalothrin in on freshwater and estuarine fishSpecies Study 

Guideline 

A.I. % 

A.I. 

Toxicity Endpoint (95 % Confidence Interval) μg a.i. /L 

Toxicity Classification 

Study Classification 

MRID # 

(Oncorhynchus mykiss)

(2.3-3.1) NOAEC :1.3 (mortality) 

toxic 3 

Estuarine/Marine FishSheepshead Minnow (Cyprinodon variegatus) 

72-3a lambdacyhalothri

n 

96.5 LC50 96 hr : 0.807 

(0.672-0.967) NOAEC :≥0.29 (mortality) 

very highly toxic 

Core 153506 
Β−1 

Table A2 provides the results of chronic toxicity studies of lambda-cyhalothrin 

conducted using freshwater or estuarine/marine fish. No chronic fish toxicity data was 

provided on gamma-cyhalothrin. Based on NOECs in fathead minnow and sheepshead 

minnow (0.03 versus 0.25 ppb), freshwater fish may be more sensitive to toxic effects of 

lambda-cyhalothrin than estuarine/marine fish. 

Table A2. Chronic toxicity effects of lambda-cyhalothrin in fish

Species Study 

Guidelin

e 

A.I. % 

A.I. 

Toxicity Endpoint 

(95% Confidence 

Interval) 

μg a.i. /L 

Study 

Classificatio

n 

MRID # 

Freshwater Fish

Fathead Minnow 

(Pimephales 

promelas) 

72-5 lambdacyhalothri

n 

96.7 NOAEC: 0.031 

LOAEC: 0.062 

(adult growth; 

young survival and 

growth) 

Supplement

al 

415190-

01 

Estuarine/Marine Fish

Sheepshead 

Minnow 

(Cyprinodon 

variegatus) 

72-4a lambdacyhalothri

n 

96.6 NOAEC: 0.25 

LOAEC: 0.38 

(weight of the 

survival) 

Core 152732 

Aquatic Invertebrates Toxicity

Table A3 summarizes the results from acute toxicity studies conducted using aquatic 

invertebrates of both freshwater and estuarine marine origin. In general, gamma and 

lambda-cyhalothrin and their formulated products are classified as very highly toxic to 

aquatic invertebrates. Among the freshwater invertebrates, Gammarus pulex is more 

sensitive to the test materials. Data from gamma-cyhalothrin studies suggests that 

neonate Gammarus are the most sensitive life stage with an LC50 value of 0.00048 g/L 

(ppb). Although this toxicity levels is the lowest that the reviewer has noted for any 

pesticide, problems in the study with declining test material concentrations suggest that 

a more accurate LC50 value would be lower. 
Β−2 

Table A3. Acute Toxic effects of gamma and lambda-cyhalothrin in aquatic invertebrates

Species Study 

Guideline 

A.I. % 

A.I. 

Toxicity Endpoint 

(95% Confidence 

Interval) μg a.i. /L 

Toxicity 

Classification1

Study 

Classification 

MRID # 

Freshwater Invertebrates 

Daphnia 

magna

72-2a lambdacyhalothri

n

96.5 EC50 48 hr :0.23 

(0.18-0.29) 

NOAEC : 0.04 

very highly 

toxic

Core 151599 

Daphnia 

magna

72-2 lambdacyhalothri

n

5.5 EC50 48 hr : 0.04

 (0.03-0.06) 

NOAEC: Not 

established 

very highly 

toxic 

Supplement

al 

151602 

lambdacyhalothri

n 

12.9 EC50 48 hr : 

0.065 

 (0.04-0.11) 

NOAEC: Not 

established 

very highly 

toxic 

Supplement

al 

151602 

lambdacyhalothri

n 

24 EC50 48 hr : 0.18 

 (0.14-0.23) 

NOAEC : 0.03 

(Immobility) 

very highly 

toxic 

Core 4390881

1 

lambdacyhalothri

n 

99 EC50 48 hr : 

0.051 

 (0.034-0.10) 

NOAEC : 

<0.0055 

very highly 

toxic 

Core 4544722

0 

gammacyhalothri

n 

100 EC50 48 hr : 

0.045 

 (0.020-0.079) 

NOAEC: <0.015 

very highly 

toxic 

Core 4544722

0 

gammacyhalothri

n 

100 EC50 48 hr : 

0.095 

 (0.078-0.114) 

NOAEC: <0.0263 

very highly 

toxic 

Supplement

al 

4544721

9 

gammacyhalothri

n 

14.7 EC50 48 hr : 

0.154 

 (0.099-0.310) 

NOAEC: <0.011 

very highly 

toxic 

Supplement

al 

4544722

1 

Gammaru

s pulex

72-2a lambdacyhalothri

n 

94 EC50 96 hr : 

0.007 

 (0.005-0.009) 

NOAEC : 0.0005 

very highly 

toxic 

Supplement

al 

152730 
Β−3 

Table A3. Acute Toxic effects of gamma and lambda-cyhalothrin in aquatic invertebrates

Species Study 

Guideline 

A.I. % 

A.I. 

Toxicity Endpoint 

(95% Confidence 

Interval) μg a.i. /L 

Toxicity 

Classification1

Study 

Classification 

MRID # 

(mortality) 

Gammaru

s 

pseudolim

naeus

nonguideline 

gammacyhalothri

n 

99.2 LC50: 

 0.00048 

(neonate), 

0.00385 

(juvenile), 

0.00812 (adult) 

very highly 

toxic 

Supplement

al 

4606560

1 

Estuarine/Marine Invertebrates 

Eastern 

Oyster 

(Crassostr

ea gigas) 

Mollusk 

Shell 

Depositio

n 

72-3b lambdacyhalothri

n 

96.5 LC50 48 hr : >590 

NOAEC : 590 

(immobility) 

highly toxic Core 152728 

Mysid 

Shrimp 

(Mysidops

is bahia) 

72-3c lambdacyhalothri

n 

>97 LC50 96 hr : 

0.005 

(0.004-0.006) 

NOAEC :Not 

established 

very highly 

toxic

Core 152729 

Table A4 presents the results from the chronic toxicity studies performed in Daphnia 

magna and mysid shrimp selected as surrogates for freshwater and estuarine/marine 

invertebrates, respectively. The comparison of NOECs reported for both the species 

indicates that mysid shrimp are more sensitive to lambda-cyhalothrin toxicity than 

Daphnia. A Daphnid study for gamma-cyhalothrin was not considered adequate to 

determine a toxicity endpoint due to variable exposure levels and inadequate 

quantitation of the test material. 

Table A4. Chronic toxic effects of gamma and lambda-cyhalothrin in aquatic invertebrates

Species Study 

Guidelin

e 

A.I. % 

A.I. 

Toxicity Endpoint 

(95% Confidence 

Interval) 

μg a.i. /L 

Study 

Classification 

MRID # 

Freshwater Invertebrates

Daphnia 

magna

72-4b 

 

lambdacyhalothrin 92.8 NOAEC: 0.004 

LOAEC:0.005 

Supplemental 152733 
Β−4 

Table A4. Chronic toxic effects of gamma and lambda-cyhalothrin in aquatic invertebrates

Number of 

young/female 

lambdacyhalothrin 96.6 NOAEC: 0.002 

LOAEC: 0.0035 

Number of 

young/female, Total 

young 

Supplemental 41217501 

gammacyhalothrin 100 Not Available Invalid 45447222 

Estuarine/Marine Invertebrates

Mysid 72-4b 

 

98.5 NOAEC: 0.0002 

LOAEC: 0.0005

Number of young per 

reproductive day and 

Number of 

young/treatment 

 Core MRID (not 

available) 

Accession 

Number 

073989 

Aquatic Plants Toxicity

There is no study reported testing the effects of gamma or lambda-cyhalothrin on 

aquatic vascular plants. Also no studies are reported on non-vascular plants of 

estuarine/marine origin (e.g., marine diatoms). Three studies conducted using aquatic 

non-vascular plant (freshwater green algae) reported the EC50 as >310 ppb. The results 

of lambda-cyhalothrin on freshwater green algae are summarized in Table A5. 

Table A5. Acute Toxic Effects of gamma and lambda-cyhalothrin on aquatic plants

Species Study 

Guidelin

e 

A.I. % 

A.I. 

Toxicity 

Endpoint 

μg a.i. /L 

Study 

Classificatio

n 

MRID # 

Freshwater Non-vascular Plants 

Green Algae

Selenastrum 

i t

123-2 

gammacyhalothrin 100 EC50 96 hr 

:>2850 

NOAEC : <1340 

Supplement

al 

45447406 
Β−5 

Table A5. Acute Toxic Effects of gamma and lambda-cyhalothrin on aquatic plants

gammacyhalothrin 14.7 Cell density

EC5072 hr: 

15000 

NOAEC: 5480 

Growth rate

EC5072 

hr:41300 

NOAEC: 5480 

Area under 

curve

EC5072 

hr:16100 

NOAEC: N.R. 

Supplement

al 

45447407 

lambdacyhalothrin 96.5 EC50 96 hr :>310 

NOAEC : ≥310 

Supplemental 152731 

Terrestrial Toxicity Studies

Avian Toxicity

Gamma and lambda-cyhalothrin are considered to be slightly toxic or practically non-toxic to 

water fowl and upland game birds with acute or subacute exposures. Sublethal effects for 

gamma-cyhalothrin exposure were noted at the lowest test concentrations in some studies. 

Sublethal effects included head twitching and decreased food consumption and weight gain. 

Results from a lambda-cyhalothrin waterfowl reproduction study indicated that eggs laid, eggs 

set, eggs cracked, viable embryos, live embryos, normal hatchlings and 14-day old survivors 

were not affected at levels up to 30ppm. There is no reproduction study available for lambdacyhalothrin on bobwhite quail and no reproductive study on any avian species for gammacyhalothrin. 

Summary of the acute and chronic avian studies are presented in Table A6. 

Table A6. Avian toxicity studies of gamma and lambda-cyhalothrin

Species Study 

Guideline 

A.I. % 

A.I. 

Toxicity Endpoint 

(Confidence 

Interval) 

Toxicity 

Classification 

Study 

Classification 

MRID # 

Bobwhite quail 

(Colinus 

virginianus) 

71-1 gammacyhalothrin 14.7 LD50: > 2000 

NOAEL (head 

twitching): <480 

mg/Kg BW 

Practically non 

toxic 

Core 45447211 

Bobwhite quail 

(Colinus 

virginianus) 

71-1a gammacyhalothrin 100 LD50: > 2000 

NOAEL (BW, 

food 

Practically non 

toxic 

Core 45447210 
Β−6 

Table A6. Avian toxicity studies of gamma and lambda-cyhalothrin

consumption): 

<480 mg/Kg BW 

Mallard duck 

(Anas 

platyrhynchos) 

71-1a lambdacyhalothrin 96 LD50 : > 3950 

mg/Kg BW 

Practically non 

toxic 

Core 151594 

Mallard duck 

(Anas 

platyrhynchos) 

71-2 gammacyhalothrin 100 LC50: >4430 

NOEC (bwt): 

<617 mg/Kg diet 

Practically non 

toxic 

Core 45447213 

Bobwhite quail 

(Colinus 

virginianus) 

71-2a gammacyhalothrin 100 LC50: 2794 

NOEC (mortality 

and bwt): 617 

mg/Kg diet 

Slightly toxic Core 45447212 

Bobwhite quail 

(Colinus 

virginianus) 

71-2a lambdacyhalothrin 99.6 LC50 : >5300 

mg/Kg diet 

Practically non 

toxic 

Core 151596 

Mallard duck 

(Anas 

platyrhynchos) 

71-2b lambdacyhalothrin 96.5 LC50 : 3948 

mg/Kg diet 

Slightly toxic Core 151595 

Mallard duck 

 (Anas 

platyrhynchos) 

71-4b lambdacyhalothrin 96.3 NOAEC : ≥30 mg 

a.i./kg diet 

(highest dose 

tested) 

- Core 41512101 

Mammalian Toxicity

Mammalian toxicological studies were conducted with gamma-cyhalothrin in order to 

compare and bridge the results to the existing toxicological data for lambda-cyhalothrin 

and cyhalothrin. The following studies were conducted with gamma-cyhalothrin: six 

acute toxicity studies, a 28-day dietary toxicity study in rats, a 90-day dietary toxicity 

study in rats, a developmental toxicity study in rats and a complete battery of 

genotoxicity studies. Summaries of the gamma-cyhalothrin studies that are normally 

used in ecological risk assessment are presented below. 

Comparative results for the toxicological studies with lambda-cyhalothrin and/or 

cyhalothrin were obtained from the EU monograph and/or the review report for lambdacyhalothrin (EU Review Programme on Active Substances in Plant Protection Products, 

lambda-cyhalothrin, Annex B, B-5: Toxicology and Metabolism, KEMI, National 

Chemicals Inspectorate, Solna, Sweden, June, 1996; Review Report for the Active 

Substance lambda-cyhalothrin, European Commission, Directorate-General Health & 

Consumer Protection, 7572/VI/97-final, 25 January 2001) and/or Environmental Health 

Criteria 99, Cyhalothrin, World Health Organization, Geneva, 1990.

Rat Acute Oral Toxicity
Β−7 

Gamma-cyhalothrin (DE-225) was given as single oral doses to male and female Wistar 

Han rats at doses up to 75 mg/kg bw. Toxic signs included salivation, incoordination, 

tremor, soft or watery feces and pupil dilation. These signs of toxicity had disappeared 

within 4 days in the rats that survived. The acute oral LD50 was >50 mg/kg bw in males 

and 55 mg/kg bw in females. 

The acute oral toxicity was also evaluated in the rat for cyhalothrin and lambdacyhalothrin in similar studies. Signs of toxicity included piloerection, salivation, 

incoordination, subdued behaviour and incontinence. The acute oral LD50 for 

cyhalothrin was 166 mg/kg bw, males and 144 mg/kg bw, females and for lambdacyhalothrin, 79 mg/kg bw, males and 56 mg/kg bw, females.

Summary of Rat Short Term Toxicity

The short-term toxic effects due to gamma-cyhalothrin, lambda-cyhalothrin and 

cyhalothrin are similar at levels high enough to cause the effects. Moreover, they occur 

at similar dose levels for the three compounds. Clinical signs characteristic of 

pyrethroid toxicity were seen for gamma-cyhalothrin (≥125 ppm) and cyhalothrin (≥250 

ppm) in the 28-day studies. They also occurred at 100 ppm gamma-cyhalothrin in the 

90-day study. Decreased body weight gain was a consistent effect at high dose level in 

the 28-day and 90-day studies as was reduced food consumption. Liver weight was 

increased in most of the studies at the higher dose levels. Increased liver APDM 

activity and SER, which are adaptive changes, were shown in the cyhalothrin and 

lambda-cyhalothrin studies but not for gamma-cyhalothrin. There were no treatment 

related histopathological effects in a range of tissues including the liver and nervous 

tissue in any study.

Table A7. Acute mammalian (rat) toxicity of pyrethroid insecticides containing gammacyhalothrin.

Pyrethroid type Cyhalothrin Lamda-cyhalothrin Gamma-cyhalothrin 

Technical 

Acute Oral -Rat LD50 : 243 mg/kg 

(m) 

144 mg/kg (f) 

Tox.Cat. II 

LD50 : 79 mg/kg (m) 

56 mg/kg (f) 

Tox.Cat. II 

LD50 :> 50 mg/kg (m) 

55 mg/kg (f) 

Tox.Cat. II 

Formulations 

GF-231 (15% A.I.) Karate Z (23% A.I.) Grenade (20% A.I.) 

Acute Oral -Rat LD50 : 2250 mg/kg 

Tox.Cat. IV 

LD50 : 245 mg/kg 

Tox.Cat. II 

LD50 : 122 mg/kg 

Tox.Cat. II 

 
Β−8 

Table A8. Rat 90-day feeding study summary for pyrethroid inseciticdes containing gamma-cyhalothrin.

 

 

Selected Parameters Gamma-cyhalothrin Lambda-cyhalothrin Cyhalothrin 

Levels tested (ppm) 0, 2.5, 10, 50, 100 0, 10, 50, 250 0, 10, 50, 250 

Dosages (mg/kg bw/day) 0, 0.2, 0.7, 3.4, 6.6 (m) 

0, 0.2, 0.8, 4.2, 8.0 (f) 

0, 0.5, 2.6, 14 (m) 

0, 0.6, 3.2, 15 (f) 

0, 0.6, 2.6, 14 (m) 

0, 0.6, 3.2, 15 (f) 

Neurotoxic signs were seen at 100 ppm > 250 ppm1 250 ppm1

Decreased body wt gain were 

seen at: 

100 ppm 250 ppm 250 ppm 

Decreased food consumption 

were seen at: 

100 ppm 250 ppm > 250 ppm1

Increased liver weight and/or 

ADPM activity 2

100 ppm 50 ppm > 250 ppm1

NOAEL 50 ppm 50 ppm 50 ppm 

Non-Target Insect Toxicity

Gamma and lambda-cyhalothrin as well as their formulated products are highly toxic to honey bees in the 

acute contact as well as oral toxicity studies (Table A9). 

Table A9. Nontarget insect toxicity studies of gamma and lambda-cyhalothrin

Species A.I. Study 

Guideline 

% 

A.I. 

Toxicity 

Endpoint 

(95 % 

Confidence 

Interval) 

Toxicity 

Classification 

Study 

Classification 

MRID # 

Honey 

bees 

(Apis 

mellifera)

lambdacyhalothrin 141-1 

Contact 

Oral

96 

96 

LD50 : 0.038 

μg a.i./bee 

LD50 : 0.909 

μg a.i./bee 

Highly Toxic 

Highly Toxic 

Core 

Core 

40052409 

40052409

lambdacyhalothrin

141-1 

Contact 

Oral 

5.04 

5.04 

LD50: 0.098 

μg a.i./bee 

LD50:0.483 

μg a.i./bee 

Highly Toxic

Highly Toxic

Core 

Core 

40052409 

40052409 
Β−9 

Table A9. Nontarget insect toxicity studies of gamma and lambda-cyhalothrin

gamma 

cyhalothrin

141-1 

Contact 

100 LD50: 

0.0061 μg 

a.i./bee 

Highly Toxic Core 45464802 

gamma 

cyhalothrin

141-1 

Contact 

14.7 LD50: 0.030 

μg 

formulation 

/bee 

Highly Toxic Supplement

al 

45464803 

gamma 

cyhalothrin

Nonguideline 

Oral 

14.7 LD50: 1.26 

μg 

formulation./

bee 

Highly Toxic Supplement

al 

45464804 

lambdacyhalothrin

141-2 

(foliage) 

PP3

21 

LT50 : 4-12 

hours for 

0.013 

lb/acre; 23 

hrs for 

0.031 

lb/acre 

NOAEL: 24-

48 hrs for 

0.013 

lb/acre and 

96 hrs for 

0.031 

lb/acre 

- Core 40436302 

gammacyhalothrin

141-2 

(foliage) 

14.7 RT50:>17 g 

a.i./ha - Core 45464805 
Χ−10 

Appendix C. 

Aerial high drift scenario input summary:

AgDRIFT® Input Data Summary 

--General-- 

Tier: III 

Title: Untitled 

Notes: 

Calculations Done: Yes 

Run ID: AgDRIFT® high rate 15 mph v fine.agd 2.01 02-24-2004 14:02:41 

Default values appear when they differ from the Current values. 

--Aircraft-- ----------Current----------- ----------Default----------- 

Name Air Tractor AT-401 

Type Basic 

Boom Height (ft) 10 

Flight Lines 20 

Wing Type Fixed-Wing 

Semispan (ft) 24.5 

Typical Speed (mph) 119.99 

Biplane Separation (ft) 0 

Weight (lbs) 6000 6000 

Planform Area (ft2) 294 

Propeller RPM 2000 

Propeller Radius (ft) 4.5 

Engine Vert Distance (ft) -1.2 

Engine Fwd Distance (ft) 11.9 

-Drop Size Distribution 1- ----------Current----------- ----------Default----------- 

Name ASAE Very Fine ASAE Fine to Medium 

Type Basic 

Drop Categories # Diam (um) Frac Diam (um) Frac 

 1 10.77 0.0148 10.77 0.0010 

 2 16.73 0.0182 16.73 0.0003 

 3 19.39 0.0158 19.39 0.0007 

 4 22.49 0.0113 22.49 0.0003 

 5 26.05 0.0127 26.05 0.0007 

 6 30.21 0.0260 30.21 0.0010 

 7 35.01 0.0425 35.01 0.0010 

 8 40.57 0.0568 40.57 0.0020 

 9 47.03 0.0690 47.03 0.0033 
Χ−11 

 10 54.50 0.0733 54.50 0.0053 

 11 63.16 0.0607 63.16 0.0067 

 12 73.23 0.0548 73.23 0.0090 

 13 84.85 0.0645 84.85 0.0133 

 14 98.12 0.0713 98.12 0.0223 

 15 113.71 0.0702 113.71 0.0330 

 16 131.73 0.0645 131.73 0.0393 

 17 152.79 0.0653 152.79 0.0480 

 18 177.84 0.0720 177.84 0.0647 

 19 205.84 0.0588 205.84 0.0830 

 20 238.45 0.0287 238.45 0.1147 

 21 276.48 0.0225 276.48 0.1283 

 22 320.60 0.0137 320.60 0.1380 

 23 372.18 0.0060 372.18 0.1127 

 24 430.74 0.0027 430.74 0.0640 

 25 498.91 0.0018 498.91 0.0440 

 26 578.54 0.0010 578.54 0.0317 

 27 670.72 0.0010 670.72 0.0203 

--Nozzle Distribution-- ----------Current----------- ----------Default----------- 

Name Nozzles for Air Tractor A... 

Type Basic 

Horiz Distance Limit (%) 0 

Boom Length (%) 76.3 

Nozzle DSD & Locations # DSD H(ft) V(ft) F(ft) DSD H(ft) V(ft) F(ft) 

 1 1 -18.7 0 0 

 2 1 -17.79 0 0 

 3 1 -16.87 0 0 

 4 1 -15.96 0 0 

 5 1 -15.05 0 0 

 6 1 -14.14 0 0 

 7 1 -13.22 0 0 

 8 1 -12.31 0 0 

 9 1 -11.4 0 0 

 10 1 -10.49 0 0 

 11 1 -9.58 0 0 

 12 1 -8.66 0 0 

 13 1 -7.75 0 0 

 14 1 -6.84 0 0 

 15 1 -5.93 0 0 

 16 1 -5.02 0 0 

 17 1 -4.1 0 0 

 18 1 -3.19 0 0 

 19 1 -2.28 0 0 

 20 1 -1.37 0 0 
Χ−12 

 21 1 -0.456 0 0 

 22 1 0.456 0 0 

 23 1 1.37 0 0 

 24 1 2.28 0 0 

 25 1 3.19 0 0 

 26 1 4.1 0 0 

 27 1 5.02 0 0 

 28 1 5.93 0 0 

 29 1 6.84 0 0 

 30 1 7.75 0 0 

 31 1 8.66 0 0 

 32 1 9.58 0 0 

 33 1 10.49 0 0 

 34 1 11.4 0 0 

 35 1 12.31 0 0 

 36 1 13.22 0 0 

 37 1 14.14 0 0 

 38 1 15.05 0 0 

 39 1 15.96 0 0 

 40 1 16.87 0 0 

 41 1 17.79 0 0 

 42 1 18.7 0 0 

--Swath-- ----------Current----------- ----------Default----------- 

Swath Width 60 ft 

Swath Displacement 0.3702 x Swath Width 

Half Boom No 

--Spray Material-- ----------Current----------- ----------Default----------- 

Name Water 

Type Basic 

Nonvolatile Rate (lb/ac) 0.272 0.501 

Active Rate (lb/ac) 0.04 0.2505 

Spray Volume 

 Rate (gal/ac) 5 2 

Specific Gravity 1 

Evaporation 

 Rate (μm2/deg C/sec) 84.76 

--Meteorology-- ----------Current----------- ----------Default----------- 

Wind Speed (mph) 15 10 

Wind Direction (deg) -90 

Temperature (deg F) 86 

Relative Humidity (%) 50 
Χ−13 

--Transport-- ----------Current----------- ----------Default----------- 

Flux Plane (ft) 0 

--Terrain-- ----------Current----------- ----------Default----------- 

Surface Roughness (ft) 0.0246 

--Advanced-- ----------Current----------- ----------Default----------- 

Wind Speed Height (ft) 6.56 6.56 

Max Compute Time (sec) 600 

Max Downwind Dist (ft) 5200 2608.24 

Vortex Decay Rate (mph) 1.25 1.25 

Aircraft Drag Coeff 0.1 

Propeller Efficiency 0.8 

Ambient Pressure (in hg) 29.91 29.91 

Aerial low drift scenario input summary:

AgDRIFT® Input Data Summary 

--General-- 

Tier: III 

Title: Untitled 

Notes: 

Calculations Done: Yes 

Run ID: AgDRIFT® low rate 3 mph med.agd 2.01 02-24-2004 14:07:25 

Default values appear when they differ from the Current values. 

--Aircraft-- ----------Current----------- ----------Default----------- 

Name Air Tractor AT-401 

Type Basic 

Boom Height (ft) 10 

Flight Lines 20 

Wing Type Fixed-Wing 

Semispan (ft) 24.5 

Typical Speed (mph) 119.99 

Biplane Separation (ft) 0 

Weight (lbs) 6000 6000 

Planform Area (ft2) 294 

Propeller RPM 2000 

Propeller Radius (ft) 4.5 

Engine Vert Distance (ft) -1.2 

Engine Fwd Distance (ft) 11.9 
Χ−14 

-Drop Size Distribution 1- ----------Current----------- ----------Default----------- 

Name ASAE Medium ASAE Fine to Medium 

Type Basic 

Drop Categories # Diam (um) Frac Diam (um) Frac 

 1 10.77 0.0005 10.77 0.0010 

 2 16.73 0.0002 16.73 0.0003 

 3 19.39 0.0003 19.39 0.0007 

 4 22.49 0.0002 22.49 0.0003 

 5 26.05 0.0003 26.05 0.0007 

 6 30.21 0.0005 30.21 0.0010 

 7 35.01 0.0007 35.01 0.0010 

 8 40.57 0.0012 40.57 0.0020 

 9 47.03 0.0022 47.03 0.0033 

 10 54.50 0.0040 54.50 0.0053 

 11 63.16 0.0058 63.16 0.0067 

 12 73.23 0.0077 73.23 0.0090 

 13 84.85 0.0095 84.85 0.0133 

 14 98.12 0.0147 98.12 0.0223 

 15 113.71 0.0227 113.71 0.0330 

 16 131.73 0.0305 131.73 0.0393 

 17 152.79 0.0403 152.79 0.0480 

 18 177.84 0.0513 177.84 0.0647 

 19 205.84 0.0630 205.84 0.0830 

 20 238.45 0.0890 238.45 0.1147 

 21 276.48 0.1077 276.48 0.1283 

 22 320.60 0.1308 320.60 0.1380 

 23 372.18 0.1262 372.18 0.1127 

 24 430.74 0.0993 430.74 0.0640 

 25 498.91 0.0795 498.91 0.0440 

 26 578.54 0.0567 578.54 0.0317 

 27 670.72 0.0278 670.72 0.0203 

 28 777.39 0.0110 777.39 0.0093 

 29 900.61 0.0055 900.61 0.0010 

 30 1044.42 0.0045 1044.42 0.0007 

 31 1210.66 0.0035 1210.66 0.0003 

 32 1403.04 0.0030 0.00 0.0000 

--Nozzle Distribution-- ----------Current----------- ----------Default----------- 

Name Nozzles for Air Tractor A... 

Type Basic 

Horiz Distance Limit (%) 0 

Boom Length (%) 76.3 

Nozzle DSD & Locations # DSD H(ft) V(ft) F(ft) DSD H(ft) V(ft) F(ft) 

 1 1 -18.7 0 0 
Χ−15 

 2 1 -17.79 0 0 

 3 1 -16.87 0 0 

 4 1 -15.96 0 0 

 5 1 -15.05 0 0 

 6 1 -14.14 0 0 

 7 1 -13.22 0 0 

 8 1 -12.31 0 0 

 9 1 -11.4 0 0 

 10 1 -10.49 0 0 

 11 1 -9.58 0 0 

 12 1 -8.66 0 0 

 13 1 -7.75 0 0 

 14 1 -6.84 0 0 

 15 1 -5.93 0 0 

 16 1 -5.02 0 0 

 17 1 -4.1 0 0 

 18 1 -3.19 0 0 

 19 1 -2.28 0 0 

 20 1 -1.37 0 0 

 21 1 -0.456 0 0 

 22 1 0.456 0 0 

 23 1 1.37 0 0 

 24 1 2.28 0 0 

 25 1 3.19 0 0 

 26 1 4.1 0 0 

 27 1 5.02 0 0 

 28 1 5.93 0 0 

 29 1 6.84 0 0 

 30 1 7.75 0 0 

 31 1 8.66 0 0 

 32 1 9.58 0 0 

 33 1 10.49 0 0 

 34 1 11.4 0 0 

 35 1 12.31 0 0 

 36 1 13.22 0 0 

 37 1 14.14 0 0 

 38 1 15.05 0 0 

 39 1 15.96 0 0 

 40 1 16.87 0 0 

 41 1 17.79 0 0 

 42 1 18.7 0 0 

--Swath-- ----------Current----------- ----------Default----------- 

Swath Width 60 ft 

Swath Displacement 0.3702 x Swath Width 
Χ−16 

Half Boom No 

--Spray Material-- ----------Current----------- ----------Default----------- 

Name Water 

Type Basic 

Nonvolatile Rate (lb/ac) 0.051 0.501 

Active Rate (lb/ac) 0.075 0.2505 

Spray Volume 

 Rate (gal/ac) 5 2 

Specific Gravity 1 

Evaporation 

 Rate (μm2/deg C/sec) 84.76 

--Meteorology-- ----------Current----------- ----------Default----------- 

Wind Speed (mph) 3 10 

Wind Direction (deg) -90 

Temperature (deg F) 86 

Relative Humidity (%) 50 

--Transport-- ----------Current----------- ----------Default----------- 

Flux Plane (ft) 0 

--Terrain-- ----------Current----------- ----------Default----------- 

Surface Roughness (ft) 0.0246 

--Advanced-- ----------Current----------- ----------Default----------- 

Wind Speed Height (ft) 6.56 6.56 

Max Compute Time (sec) 600 

Max Downwind Dist (ft) 5200 2608.24 

Vortex Decay Rate (mph) 1.25 1.25 

Aircraft Drag Coeff 0.1 

Propeller Efficiency 0.8 

Ambient Pressure (in hg) 29.91 29.91 

Ground boom high drift scenario inputs: 

AgDRIFT® Input Data Summary 

--General-- 

Tier: I 

Title: Untitled 

Notes: 

Default values appear when they differ from the Current values. 
Χ−17 

 ----------Current----------- ----------Default----------- 

Application Method Ground Aerial 

Application Selection High Boom, ASAE Very Fine... ASAE Fine 

Ground boom low drift scenario inputs:

AgDRIFT® Input Data Summary 

--General-- 

Tier: I 

Title: Untitled 

Notes: 

Default values appear when they differ from the Current values. 

 ----------Current----------- ----------Default----------- 

Application Method Ground Aerial 

Application Selection Low Boom, ASAE Fine to Me... ASAE Fine 

Airblast high drift scenario inputs: 

AgDRIFT® Input Data Summary 

--General-- 

Tier: I 

Title: Untitled 

Notes: 

Default values appear when they differ from the Current values. 

 ----------Current----------- ----------Default----------- 

Application Method Orchard Airblast Aerial 

Application Selection Sparse (Young, Dormant) Aerosol to Very Fine 

Airblast low drift scenario inputs:

AgDRIFT® Input Data Summary 

--General-- 

Tier: I 

Title: Untitled 

Notes: 

Default values appear when they differ from the Current values. 
Χ−18 

 ----------Current----------- ----------Default----------- 

Application Method Orchard Airblast Aerial 

Application Selection Normal (Stone and Pome Fr... Aerosol to Very Fine