Section 18 Emergency Specific Exemption

2016

Transform® WG Insecticide

Sulfoxaflor

EPA Reg. No 62719-625

For the control of the sugarcane aphid, Melanaphis sacchari 

in sorghum in Texas

Dow AgroSciences
2016 FIFRA SECTION 18 

General information requirements of §40 CFR 166.20(a) in an application for a specific 

exemption.

 SPECIFIC

QUARANTINE

PUBLIC HEALTH

i. This application to the Administrator of the Environmental Protection Agency 

(EPA) for a specific exemption to authorize the use of Sulfoxaflor (Transform® 

WG Insecticide EPA Reg. No. 62719-625) to control the sugarcane aphid, 

Melanaphis sacchari in sorghum by the Texas Department of Agriculture. Any 

questions related to this request should be addressed to:

Dale R. Scott

Coordinator for Pesticide Product Evaluation and Registration 

Texas Department of Agriculture

P.O. Box 12847

Austin, TX 78711

Phone: (512) 936-2535

Fax: (888) 216-9860

dale.scott@TexasAgriculture.gov

ii. The following qualified experts are also available to answer questions:

University Representatives:

Dr. M.O. (Mo) Way

Professor of Entomology

Texas A&M AgriLife Research and Extension Center

1509 Aggie Drive

Beaumont, TX 77713

409.752.2741 x 2231 (office)

moway@aesrg.tamu.edu

TYPE OF EXEMPTION BEING REQUESTED

SECTION 166.20(a)(1): IDENTITY OF CONTACT PERSONS
Raul T. Villanueva - Ph. D.

Texas A&M AgriLife Extension

Assistant Professor and Entomologist 

2401 East Highway 83, Weslaco, TX 78596

rtvillanueva@ag.tamu.edu

Tel: (956) 968-5581

Tel: (956) 969-5604

Fax: (956) 969-5639

Registrant Representative:

Tami Jones-Jefferson 

U.S. Regulatory Leader 

U.S. Regulatory & Government Affairs - Crop Protection

Dow AgroSciences

9330 Zionsville Road

Indianapolis IN 46268

phone: 317.337.3574 

email: tjjonesjefferson@dow.com

i. Common Chemical Name (Active Ingredient): Sulfoxaflor

Trade Name and EPA Reg. No.: Transform® WG Insecticide, EPA Reg. No. 

62719-625

 Formulation: Active Ingredient 50%

 

i. Sites to be treated:

Sorghum fields (grain and forage) with the sugarcane aphid, Melanaphis sacchari

statewide.

ii. Method of Application:

Applications will be made by foliar application.

iii. Rate of Application:

0.75 – 1.5 oz of Transform® WG/acre (0.023 – 0.047 lb ai/acre)

iv. Maximum Number of Applications:

2 applications per year (maximum of 3 oz/acre (0.094 lb ai/acre)

SECTION 166.20(a)(2): DESCRIPTION OF THE PESTICIDE REQUESTED

SECTION 166.20(a)(3): DESCRIPTION OF THE PROPOSED USE
v. Total Acreage to be Treated:

According to the National Agricultural Statistics Service (NASS), 3 million acres of 

sorghum was planted in Texas in 2013. During the 2015 use season, 1,021,657 acres 

were treated with Transform® WG, according to estimates provided by Dow 

AgroSciences.

vi. Total Amount of Pesticide to be used:

According to the previously mentioned statistics, if all 3 million acres of sorghum 

were treated with the maximum rate (1.5 oz/acre or 0.047 lb ai/acre) and the 

maximum numbers of applications are made (2 applications or 3.0 oz/acre or 0.094 lb 

ai/acre) then 70,313.5 gallons of Transform® WG would be used in 2016. 

vii. Restrictions and Requirements:

 Preharvest Interval: Do not apply within 7 days of harvest for grain or 14 days 

of harvest for forage, hay or stover.

 Re-Entry Interval (REI): 24 hrs

 Minimum Treatment Interval: Do not make applications less than 14 days 

apart.

 Do not make more than two applications per acre per year.

 Do not apply more than a total of 3.0 oz of Transform WG (0.09 lb ai of 

sulfoxaflor) per acre per year.

Duration of the Proposed use:

Early Spring through Late Fall

viii. Earliest Possible Harvest Date:

Late May in South Texas

Registered Alternative Pesticides:

Of the registered alternative pesticides, only Dimethoate 4 EC (dimethoate, EPA Reg. No. 

19713-231) has provided adequate control. Dimethoate is an organophosphate which is labeled 

for use on sorghum at 1 pint per acre. Dimethoate, which is highly toxic to bees, has a use

restriction that does not allow its use during pollen shed in sorghum. Insects have historically

shown resistance to organophosphates. Three other pesticides registered for use in sorghum did 

not provide adequate control of the aphid. Those pesticides are:

Karate® with ZeonTM Technology (Lambda Cyholothrin 22.8%, EPA Reg. No. 100-1097)

Lorsban® Advanced, others (Chlorpyrifos 40.2%, EPA Reg. No. 62719-591)

Asana® XL (Esfenvalerate 8.4%, EPA Reg. No. 352-515)

Of the above mentioned insecticides, Karate® and Asana® are pyrethroids and Lorsban® is an 

organophosphate. Both pyrethroids and organophosphates have shown resistance potential. In 

field tests conducted in 2013 by Texas A&M AgriLife professionals, Karate® and Asana® both 

SECTION 166.20(a)(4): ALTERNATIVE METHODS OF CONTROL
provided some initial population reduction when used at labeled rates. However, population 

spikes were observed soon after treatments in some instances. Chlorpyrifos did not provide 

satisfactory control at labeled rates. 

Sivanto® was approved for use in 2015 and is available to producers for SCA control. Even 

though Sivanto® is available, Transform® is still needed to prevent resistance build up, which is 

common in aphids. Transform® is also needed due to the fact that it has a 7 day pre harvest 

interval, whereas Sivanto® has a 14 day restriction. The 7 day window is needed to treat late 

season aphid infestations prior to harvest. Without the late season control prior to harvest, aphid 

populations can create large amounts of honeydew with creates major problems with the harvest 

equipment and lodging of the sorghum, preventing harvest all together.

A few varieties of resistant sorghum have been identified by researchers, but sufficient quantities 

of agronomically acceptable cultivars will not be available for the 2016 planting season. 

Table to Address Issues with Registered Alternatives: 

Chemical

(active ingredient)

Application 

Type (soil, seed, 

foliar, etc.)

Number of 

Applications/

growing 

season

Comments- reason insecticide 

unsuitable

Imidacloprid Seed 1 Due to the nature of the application 

as a seed treatment, it is doubtful 

that it can provide season-long 

control. Further tests will be 

evaluated this season.

Clothianidin Seed 1 Due to the nature of the application 

as a seed treatment, it is doubtful 

that it can provide season-long

control. Further tests will be 

evaluated this season.

Thiamethoxam Seed 1 Due to the nature of the application 

as a seed treatment, it is doubtful 

that it can provide season-long 

control. Further tests will be 

evaluated this season.

Dimethoate Foliar 3 Provided inconsistent control. Has 

restriction of no applications during 

pollen shed due to the toxicity to 

bees. 28 day PHI 

Chlorpyrifos Foliar 3 Results of less than satisfactory 

control. PHI prevents late season 

application. (30 days PHI of 1 

pint/acre, 60 days PHI of 1+ 

pints/acre)

Lambda Cyhalothrin Foliar 3 (can only Good initial control, but flared 
apply twice 

after crop has 

emerged and 

once after is 

in soft dough 

stage.

populations in test. 30 day PHI.

Esfenvalerate Foliar 1 Good initial control, but residual 

was short, actually flaring 

populations. 21 day PHI

Turbufos Soil - Band @ 

planting

1 - 5cm wide 

band

Will not provide season long 

control.

Two replicated field trials were conducted on the aphid in 2013. The first was conducted by Dr. 

Mo Way in August in China, Texas. The second replicated test was conducted in Weslaco, 

Texas, by Dr. Raul Villanueva and D. Sekula. In both trials, data showed that Transform® WG 

at 0.75/acre provided good control of Melanaphis sacchari. 

Several tests were conducted during the 2014 and 2015 growing season. These trials confirmed 

that sulfoxaflor gave outstanding control when compared to other registered products in 

controlling Melanaphis sacchari in sorghum production. The applications allowed under the 

section 18 exemption also showed overwhelming success of the insecticide in Texas. 

The following documents provide data to support the efficacy of sulfoxaflor for control of 

Melanaphis sacchari in sorghum:

2014 Grain Sorghum Insecticide Efficacy Trials (Attachment A)

2015 Sugarcane Aphid Insecticide Efficacy Trial (Attachment B)

Sorghum Insecticide Screening for 2014 Annual Report (Attachment C)

Dr. Way ALL DATA for Sorghum Insecticide Screening (Attachment D)

Brewer Data (Attachment E)

An Integrated Regional Response to an Invasive Aphid Pest of Sorghum (Attachment F)

2015 Occurrence Maps (Attachment G)

Based on the 2013 Weslaco data it seemed that dimethoate worked as well as Transform, (see 

graph bellow for precounting, 7dd and 14daa) however Dr. Kerns and Mexican colleagues did 

not have good results. In addition the PHI of Dimethoate is 38 days. In the Lorsban and Asana 

plots you can see increase of populations at 14 daa. The time was flowering to grain filling. By 

the way grains did not fill and they looked wrinkled and dehydrated.

SECTION 166.20(a)(5): EFFICACY OF USE PROPOSED UNDER SECTION 18
Pre-Count 7dd 14dd

Acute Assessment

Food consumption information from the USDA 1994-1996 and 1998 Nationwide Continuing 

Surveys of Food Intake by Individuals (CSFII) and maximum residues from field trials rather 

than tolerance-level residue estimates were used. It was assumed that 100% of crops covered by 

the registration request are treated and maximum residue levels from field trials were used.

Drinking water. Two scenarios were modeled, use of sulfoxaflor on non-aquatic row and orchard 

crops and use of sulfoxaflor on watercress. For the non-aquatic crop scenario, based on the 

Pesticide Root Zone Model/Exposure Analysis Modeling System (PRZM/EXAMS) and 

Screening Concentration in Ground Water (SCI-GROW) models, the estimated drinking water 

concentrations (EDWCs) of sulfoxaflor for acute exposures are 26.4 ppb for surface water and 

69.2 ppb for ground water. For chronic exposures, EDWCs are 13.5 ppb for surface water and 

69.2 ppb for ground water. For chronic exposures for cancer assessments, EDWCs are 9.3 ppb 

for surface water and 69.2 ppb for ground water. For the watercress scenario, the EDWCs for 

SECTION 166.20(a)(6): EXPECTED RESIDUES FOR FOOD USES

Michael Hare, Ph.D.
surface water are 91.3 ppb after one application, 182.5 ppb after two applications and 273.8 ppb 

after three applications. 

Dietary risk estimates using both sets of EDWCs are below levels of concern. The non-aquaticcrop EDWCs are more representative of the expected exposure profile for the majority of the 

population. Also, water concentration values are adjusted to take into account the source of the 

water; the relative amounts of parent sulfoxaflor, X11719474, and X11519540; and the relative 

liver toxicity of the metabolites as compared to the parent compound. 

For acute dietary risk assessment of the general population, the groundwater EDWC is greater 

than the surface water EDWC and was used in the assessment. The residue profile in 

groundwater is 60.9 ppb X11719474 and 8.3 ppb X11519540 (totaling 69.2 ppb). Parent 

sulfoxaflor does not occur in groundwater. The regulatory toxicological endpoint is based on 

neurotoxicity. 

For acute dietary risk assessment of females 13-49, the regulatory endpoint is attributable only to 

the parent compound; therefore, the surface water EDWC of 9.4 ppb was used for this 

assessment. 

A tolerance of 0.3 ppm for sulfoxaflor on grain sorghum has been established. There is no 

expectation of residues of sulfoxaflor and its metabolites in animal commodities as a result of the 

proposed use on sorghum. Thus, animal feeding studies are not needed, and tolerances need not 

be established for meat, milk, poultry, and eggs.

Drinking water exposures are the driver in the dietary assessment accounting for 100% of the 

exposures. Exposures through food (sorghum grain and syrup) are zero. 

The acute dietary exposure from food and water to sulfoxaflor is 16% of the aPAD for children 

1-2 years old and females 13-49 years old, the population groups receiving the greatest exposure.

Chronic Assessment

The same refinements as those used for the acute exposure assessment were used, with two 

exceptions: (1) average residue levels from crop field trials were used rather than maximum 

values and (2) average residues from feeding studies, rather than maximum values, were used to 

derive residue estimates for livestock commodities. It was assumed that 100% of crops are 

treated and average residue levels from field trials were used.

For chronic dietary risk assessment, the toxicological endpoint is liver effects, for which it is 

possible to account for the relative toxicities of X11719474 and X11519540 as compared to 

sulfoxaflor. The groundwater EDWC is greater than the surface water EDWC. The residue 

profile in groundwater is 60.9 ppb X11719474 and 8.3 ppb X11519540. Adjusting for the 

relative toxicity results in 18.3 ppb equivalents of X11719474 and 83 ppb X11519540 (totaling 

101.3 ppb). The adjusted groundwater EDWC is greater than the surface water EDWC (9.3 ppb) 

and was used to assess the chronic dietary exposure scenario.
The maximum dietary residue intake via consumption of sorghum commodities would be only a 

small portion of the RfD (<0.001%) and therefore, should not cause any additional risk to 

humans via chronic dietary exposure. Consumption of sorghum by sensitive sub-populations 

such as children and non-nursing infants is essentially zero. Thus, the risk of these 

subpopulations to chronic dietary exposure to sulfoxaflor used on grain sorghum would be 

insignificant.

The major contributor to the risk was water (100%). There was no contribution from grain 

sorghum to the dietary exposure. All other populations under the chronic assessment show risk 

estimates that are below levels of concern. 

Chronic exposure to sulfoxaflor from food and water is 18% of the cPAD for infants, the 

population group receiving the greatest exposure. There are no residential uses for sulfoxaflor.

Short-term risk. Because there is no short-term residential exposure and chronic dietary exposure 

has already been assessed, no further assessment of short-term risk is necessary, the chronic 

dietary risk assessment for evaluating short-term risk for sulfoxaflor is sufficient.

Intermediate-term risk. Intermediate-term risk is assessed based on intermediate-term residential 

exposure plus chronic dietary exposure. Because there is no residential exposure and chronic 

dietary exposure has already been assessed, no further assessment of intermediate-term risk is 

necessary.

Cumulative effects. Sulfoxaflor does not share a common mechanism of toxicity with any other 

substances, and does not produce a toxic metabolite produced by other substances. Thus, 

sulfoxaflor does not have a common mechanism of toxicity with other substances. 

Cancer. A nonlinear RfD approach is appropriate for assessing cancer risk to sulfoxaflor. This 

approach will account for all chronic toxicity, including carcinogenicity that could result from 

exposure to sulfoxaflor. Chronic dietary risk estimates are below levels of concern; therefore, 

cancer risk is also below levels of concern.

There is a reasonable certainty that no harm will result to the general population, or to infants 

and children from aggregate exposure to sulfoxaflor as used in this emergency exemption 

request.

Human Health

Toxicological Profile

SECTION 166.20(a)(7): DISCUSSION OF RISK INFORMATION

Human Health Effects – Michael Hare, Ph.D.

Ecological Effects – David Villarreal, Ph.D.

Environmental Fate – David Villarreal, Ph.D.
Sulfoxaflor is a member of a new class of insecticides, the sulfoximines. It is an activator of the 

nicotinic acetylcholine receptor (nAChR) in insects and, to a lesser degree, mammals. The 

nervous system and liver are the target organs, resulting in developmental toxicity and 

hepatotoxicity.

Developmental toxicity was observed in rats only. Sulfoxaflor produced skeletal abnormalities 

likely resulting from skeletal muscle contraction due to activation of the skeletal muscle nAChR 

in utero. Contraction of the diaphragm, also related to skeletal muscle nAChR activation, 

prevented normal breathing in neonates and increased mortality. The skeletal abnormalities 

occurred at high doses while decreased neonatal survival occurred at slightly lower levels.

Sulfoxaflor and its major metabolites produced liver weight and enzyme changes, and tumors in 

subchronic, chronic and short-term studies. Hepatotoxicity occurred at lower doses in long-term 

studies compared to short-term studies.

Reproductive effects included an increase in Leydig cell tumors which were not treatment related 

due to the lack of dose response, the lack of statistical significance for the combined tumors, and 

the high background rates for this tumor type in F344 rats. The primary effects on male 

reproductive organs are secondary to the loss of normal testicular function due to the size of the 

Leydig Cell adenomas. The secondary effects to the male reproductive organs are also not 

treatment related. It appears that rats are uniquely sensitive to these developmental effects and 

are unlikely to be relevant to humans.

Clinical indications of neurotoxicity were observed at the highest dose tested in the acute 

neurotoxicity study in rats. Decreased motor activity was also observed in the mid- and highdose groups. Since the neurotoxicity was observed only at a very high dose and many of the 

effects are not consistent with the perturbation of the nicotinic receptor system, it is unlikely that 

these effects are due to activation of the nAChR.

Tumors have been observed in rat and mouse studies. In rats, there were significant increases in 

hepatocellular adenomas in the high-dose males. In mice, there were significant increases in 

hepatocellular adenomas and carcinomas in high dose males. In female mice, there was an 

increase in carcinomas at the high dose. Liver tumors in mice were treatment-related. Leydig cell 

tumors were also observed in the high-dose group of male rats, but were not related to treatment. 

There was also a significant increase in preputial gland tumors in male rats in the high-dose 

group. Given that the liver tumors are produced by a non-linear mechanism, the Leydig cell 

tumors were not treatment-related, and the preputial gland tumors only occurred at the high dose 

in one sex of one species, the evidence of carcinogenicity was weak. 

Ecological Toxicity

Sulfoxaflor (N-[methyloxido[1-[6-(trifluoromethyl)-3-pyridinyl]ethyl]-lambda 4-sulfanylidene]) 

is a new variety of insecticide as a member of the sulfoxamine subclass of neonicotinoid 

insecticides. It is considered an agonist of the nicotinic acetylcholine receptor and exhibits 

excitatory responses including tremors, followed by paralysis and mortality in target insects. 

Sulfoxaflor consists of two diastereomers in a ratio of approximately 50:50 with each 

diastereomer consisting of two enantiomers. Sulfoxaflor is systemically distributed in plants 
when applied. The chemical acts through both contact action and ingestion and provides both 

rapid knockdown (symptoms are typically observed within 1-2 hours of application) and residual 

control (generally provides from 7 to 21 days of residual control). Incident reports submitted to 

EPA since approximately 1994 have been tracked via the Incident Data System. Over the 2012 

growing season, a Section 18 emergency use was granted for application of sulfoxaflor to cotton 

in four states (MS, LA, AR, TN). No incident reports have been received in association with the 

use of sulfoxaflor in this situation.

Sulfoxaflor is classified as practically non-toxic on an acute exposure basis, with 96-h LC50

values of >400 mg a.i./L for all three freshwater fish species tested (bluegill, rainbow trout, and 

common carp). Mortality was 5% or less at the highest test treatments in each of these studies. 

Treatment-related sublethal effects included discoloration at the highest treatment concentration 

(100% of fish at 400 mg a.i./L for bluegill) and fish swimming on the bottom (1 fish at 400 mg 

a.i./L for rainbow trout). No other treatment-related sublethal effects were reported. For an 

estuarine/marine sheepshead minnow, sulfoxaflor was also practically non-toxic with an LC50 of 

288 mg a.i./L. Sublethal effects included loss of equilibrium or lying on the bottom of aquaria at 

200 and 400 mg a.i./L. The primary degradate of sulfoxaflor is also classified as practically nontoxic to rainbow trout on an acute exposure basis (96-h LC50 >500 mg a.i./L).

Adverse effects from chronic exposure to sulfoxaflor were examined with two fish species 

(fathead minnow and sheepshead minnow) during early life stage toxicity tests. For fathead 

minnow, the 30-d NOAEC is 5 mg a.i./L based on a 30% reduction in mean fish weight relative 

to controls at the next highest concentration (LOAEC=10 mg a.i./L). No statistically significant 

and/or treatment-related effects were reported for hatching success, fry survival and length. For 

sheepshead minnow, the 30-d NOAEC is 1.3 mg a.i./L based on a statistically significant 

reduction in mean length (3% relative to controls) at 2.5 mg a.i./L. No statistically significant 

and/or treatment-related effects were reported for hatching success, fry survival and mean 

weight.

The acute toxicity of sulfoxaflor was evaluated for one freshwater invertebrate species, the water 

flea and two saltwater species (mysid shrimp and Eastern oyster). For the water flea, the 48-h 

EC50 is >400 mg a.i./L, the highest concentration tested. For Eastern oyster, new shell growth 

was significantly reduced at 120 mg a.i./L (75% reduction relative to control). The 96-h EC50 for 

shell growth is 93 mg a.i./L. No mortality occurred at any test concentration. Mysid shrimp are 

the most acutely sensitive invertebrate species tested with sulfoxaflor based on water column 

only exposures, with a 96-h LC50 of 0.67 mg a.i./L. The primary degradate of sulfoxaflor is also 

classified as practically non-toxic to the water flea (EC50 >240 mg a.i./L).

The chronic effects of sulfoxaflor to the water flea were determined in a semi-static system over 

a period of 21 days to nominal concentrations of 6.25, 12.5, 25, 50 and 100 mg a.i./L. Adult 

mortality, reproduction rate (number of young), length of the surviving adults, and days to first 

brood were used to determine the toxicity endpoints. No treatment-related effects on adult 

mortality or adult length were observed. The reproduction rate and days to first brood were 

significantly (p<0.05) different in the 100 mg a.i./L test group (40% reduction in mean number 

of offspring; 35% increase in time to first brood). No significant effects were observed on 
survival, growth or reproduction at the lower test concentrations. The 21-day NOAEC and 

LOAEC were determined to be 50 and 100 mg a.i./L, respectively.

The chronic effects of sulfoxaflor to mysid shrimp were determined in a flow-through system 

over a period of 28 days to nominal concentrations of 0.063, 0.13, 0.25, 0.50 and 1.0 mg a.i./L. 

Mortality of parent (F0) and first generation (F1), reproduction rate of F0 (number of young), 

length of the surviving F0 and F1, and days to first brood by F0 were used to determine the 

toxicity endpoints. Complete F0 mortality (100%) was observed at the highest test concentration 

of 1.0 mg a.i./L within 7 days; no treatment-related effects on F0/F1 mortality, F0 reproduction 

rate, or F0/F1 length were observed at the lower test concentrations. The 28-day NOAEC and 

LOAEC were determined to be 0.11 mg and 0.25 mg a.i./L, respectively.

Sulfoxaflor exhibited relatively low toxicity to aquatic non-vascular plants. The most sensitive 

aquatic nonvascular plant is the freshwater diatom with a 96-h EC50 of 81.2 mg a.i./L. Similarly, 

sulfoxaflor was not toxic to the freshwater vascular aquatic plant, Lemna gibba, up to the limit 

amount, as indicated by a 7-d EC50 for frond count, dry weight and growth rate of >100 mg a.i./L 

with no significant adverse effects on these endpoints observed at any treatment concentration.

Based on an acute oral LD50 of 676 mg a.i./kg bw for bobwhite quail, sulfoxaflor is considered 

slightly toxic to birds on an acute oral exposure basis. On a subacute, dietary exposure basis, 

sulfoxaflor is classified as practically nontoxic to birds, with 5-d LC50 values of >5620 mg/kgdiet for mallard ducks and bobwhite quail. The NOAEL from these studies is 5620 mg/kg-diet as 

no treatment related mortality of sublethal effects were observed at any treatment. Similarly, the 

primary degradate is classified as practically nontoxic to birds on an acute oral exposure basis 

with a LD50 of >2250 mg a.i./kg bw. In two chronic, avian reproductive toxicity studies, the 20-

week NOAELs ranged from 200 mg/kg-diet (mallard, highest concentration tested) to 1000 

mg/kg-diet (bobwhite quail, highest concentration tested). No treatment-related adverse effects 

were observed at any test treatment in these studies.

For bees, sulfoxaflor is classified as very highly toxic with acute oral and contact LD50 values of 

0.05 and 0.13 μg a.i./bee, respectively, for adult honey bees. For larvae, a 7-d oral LD50 of >0.2 

μg a.i./bee was determined (45% mortality occurred at the highest treatment of 0.2 μg a.i./bee). 

The primary metabolite of sulfoxaflor is practically non-toxic to the honey bee. This lack of 

toxicity is consistent with the cyano-substituted neonicotinoids where similar cleavage of the 

cyanide group appears to eliminate their insecticidal activity. The acute oral toxicity of 

sulfoxaflor to adult bumble bees (Bombus terrestris) is similar to the honey bee; whereas its 

acute contact toxicity is about 20X less toxic for the bumble bee. Sulfoxaflor did not demonstrate 

substantial residual toxicity to honey bees exposed via treated and aged alfalfa (i.e., mortality 

was <15% at maximum application rates). 

At the application rates used (3-67% of US maximum), the direct effects of sulfoxaflor on adult 

forager bee mortality, flight activity and the occurrence of behavioral abnormalities is relatively 

short-lived, lasting 3 days or less. Direct effects are considered those that result directly from 

interception of spray droplets or dermal contact with foliar residues. The direct effect of 

sulfoxaflor on these measures at the maximum application rate in the US is presently not known. 

When compared to control hives, the effect of sulfoxaflor on honey bee colony strength when 
applied at 3-32% of the US maximum proposed rate was not apparent in most cases. When 

compared to hives prior to pesticide application, sulfoxaflor applied to cotton foliage up to the 

maximum rate proposed in the US resulted in no discernible decline in mean colony strength by 

17 days after the first application. Longer-term results were not available from this study nor 

were concurrent controls included. For managed bees, the primary exposure routes of concern 

include direct contact with spray droplets, dermal contact with foliar residues, and ingestion 

through consumption of contaminated pollen, nectar and associated processed food provisions. 

Exposure of hive bees via contaminated wax is also possible. Exposure of bees through 

contaminated drinking water is not expected to be nearly as important as exposure through direct 

contact or pollen and nectar.

In summary, sulfoxaflor is slightly toxic to practically non-toxic to fish and freshwater water 

aquatic invertebrates on an acute exposure basis. It is also practically non-toxic to aquatic plants 

(vascular and non-vascular). Sulfoxaflor is highly toxic to saltwater invertebrates on an acute 

exposure basis. The high toxicity of sulfoxaflor to mysid shrimp and benthic aquatic insects 

relative to the water flea is consistent with the toxicity profile of other insecticides with similar 

MOAs. For birds and mammals, sulfoxaflor is classified as moderately toxic to practically nontoxic on an acute exposure basis. The threshold for chronic toxicity (NOAEL) to birds is 200 

ppm and that for mammals is 100 ppm in the diet. Sulfoxaflor did not exhibit deleterious effects 

to terrestrial plants at or above its proposed maximum application rates. 

For bees, sulfoxaflor is classified as very highly toxic. However, if this insecticide is strictly 

used as directed on the Section 18 supplemental label, no significant adverse effects are expected 

to Texas wildlife. Of course, standard precautions to avoid drift and runoff to waterways of the 

state are warranted. As stated on the Section 3 label, risk to managed bees and native pollinators 

from contact with pesticide spray or residues can be minimized when applications are made 

before 7 am or after 7 pm or when the temperature is below 55◦F at the site of application.

Environmental Fate

Sulfoxaflor is a systemic insecticide which displays translaminar movement when applied to 

foliage. Movement of sulfoxaflor within the plant follows the direction of water transport within 

the plant (i.e., xylem mobile) as indicated by phosphor translocation studies in several plants. 

Sulfoxaflor is characterized by a water solubility ranging from 550 to 1,380 ppm. Sulfoxaflor has 

a low potential for volatilization from dry and wet surfaces (vapor pressure= 1.9 x 10-8torr and 

Henry’s Law constant= 1.2 x 10-11 atm m3 mole-1, respectively at 25 °C). Partitioning coefficient 

of sulfoxaflor from octanol to water (Kow @ 20 C & pH 7= 6; Log Kow = 0.802) suggests low 

potential for bioaccumulation. No fish bioconcentration study was provided due to the low Kow, 

but sulfoxaflor is not expected to bioaccumulate in aquatic systems. Furthermore, sulfoxaflor is 

not expected to partition into the sediment due to low Koc (7-74 mL/g).

Registrants tests indicate that hydrolysis, and both aqueous and soil photolysis are not expected 

to be important in sulfoxaflor dissipation in the natural environment. In a hydrolysis study, the 

parent was shown to be stable in acidic/neutral/alkaline sterilized aqueous buffered solutions (pH 

values of 5, 7 and 9). In addition, parent chemical as well as its major degradate, were shown to 

degrade relatively slowly by aqueous photolysis in sterile and natural pond water (t1⁄2= 261 to 

>1,000 days). Furthermore, sulfoxaflor was stable to photolysis on soil surfaces. Sulfoxaflor is 
expected to biodegrade rapidly in aerobic soil (half-lives <1 day). Under aerobic aquatic 

conditions, biodegradation proceeded at a more moderate rate with half-lives ranging from 37 to 

88 days. Under anaerobic soil conditions, the parent compound was metabolized with half-lives 

of 113 to 120 days while under anaerobic aquatic conditions the chemical was more persistent 

with half-lives of 103 to 382 days. In contrast to its short-lived parent, the major degradate is 

expected to be more persistent than its parent in aerobic/anaerobic aquatic systems and some 

aerobic soils. In other soils, less persistence is expected due to mineralization to CO2 or the 

formation of other minor degradates.

In field studies, sulfoxaflor has shown similar vulnerability to aerobic bio-degradation in nine out 

of ten terrestrial field dissipation studies on bare-ground/cropped plots (half-lives were <2 days 

in nine cropped/bare soils in CA, FL, ND, ON and TX and was 8 days in one bare ground soil in 

TX). The chemical can be characterized by very high to high mobility (Kfoc ranged from 11-72 

mL g-1). Rapid soil degradation is expected to limit chemical amounts that may potentially leach 

and contaminate ground water. Contamination of groundwater by sulfoxaflor will only be 

expected when excessive rain occurs within a short period (few days) of multiple applications in 

vulnerable sandy soils. Contamination of surface water by sulfoxaflor is expected to be mainly 

related to drift and very little due to run-off. This is because drifted sulfoxaflor that reaches 

aquatic systems is expected to persist while that reaching the soil system is expected to degrade 

quickly with slight chance for it to run-off.

When sulfoxaflor is applied foliarly on growing crops it is intercepted by the crop canopy. Data 

presented above appear to indicate that sulfoxaflor enters the plant and is incorporated in the 

plant foliage with only limited degradation. It appears that this is the main source of the 

insecticide sulfoxaflor that would kill sap sucking insects. This is because washed-off 

sulfoxaflor, that reaches the soil system, is expected to degrade.

In summary, sulfoxaflor has a low potential for volatilization from dry and wet surfaces. This 

chemical is characterized by relatively higher water solubility. Partitioning coefficient of 

sulfoxaflor from octanol to water suggests low potential for bioaccumulation in aquatic 

organisms such as fish. Sulfoxaflor is resistant to hydrolysis and photolysis but transforms 

quickly in soils. In contrast, sulfoxaflor reaching aquatic systems by drift is expected to degrade 

rather slowly. Partitioning of sulfoxaflor to air is not expected to be important due to the low 

vapor pressure and Henry’s Law constant for sulfoxaflor. Exposure in surface water results from 

drifted parent as only minor amounts is expected to run-off only when rainfall and/or irrigation 

immediately follow application. The use of this insecticide is not expected to significantly 

adversely impact Texas ecosystems with use according to the Section 18 label with this 

application. Of course, caution is needed to prevent exposure to water systems because of 

toxicity issues to aquatic invertebrates. As stated on the Section 3 label, this product should 

never be applied directly to water, to areas where surface water is present or to intertidal areas 

below the mean water mark. Do not contaminate water when disposing of equipment rinsates.

Endangered and Threatened Species in Texas

No impacts are expected on endangered and threatened species by this very limited use of this 

insecticide as delineated in the Section 18 application. Sulfoxaflor demonstrates a very favorable 

ecotoxicity and fate profile as stated above and should not directly impact any protected 
mammal, fish, avian, or plant species. This product does adversely affect insects and aquatic 

invertebrates, especially bees, but the limited exposure to these species should not negatively 

affect endangered and threatened species in Texas. As always, the label precautions need be 

strictly adhered to.

For more information, see Attachment H.

The following state/federal agencies were notified of the Texas Department of Agriculture’s 

(TDA’s) actions to submit an application for a specific exemption to EPA

- Texas Commission on Environmental Quality (TCEQ), Air Quality Control

- Texas Commission on Environmental Quality (TCEQ), Water Quality

- Texas Parks and Wildlife Department

- U.S. Fish and Wildlife Department

See Attachment I for a copy of these letters.

Dow AgroScience has been notified of this agency’s intent regarding this application (see 

attached letter of support). They have also provided a copy of a label with the use directions for 

this use (although this use is dependent upon the approval of this section-18 by EPA).

The State Legislature has endowed TDA with the authority to regulate the distribution, storage, 

sale, use and disposal of pesticides in the state of Texas. In addition, the EPA/TDA grant 

enforcement agreement provides the Department with the authority to enforce the provisions of 

the FIFRA, as amended, within the state. Therefore, the Department is no lacking in authority to 

enforce the provisions of an EPA Pesticide Enforcement Specialist will make a number of 

random, unannounced calls on applicators to check for compliance with provisions of the 

specific exemption. If violations are discovered appropriate enforcement will be taken.

This is the third time TDA has applied for this specific exemption.

SECTION 166.20(a)(8): COORDINATION WITH OTHER AFFECTED STATE OR 

FEDERAL AGENCIES

SECTION 166.20(a)(9): ACKNOWLEDGEMENT BY THE REGISTRANT

SECTION 166.20(a)(10): DESCRIPTION OF PROPOSED ENFORCEMENT 

PROGRAM

SECTION 166.20(a)(11): REPEAT USES

SECTION 166.20(b)(1): NAME OF THE PEST
Melanaphis sacchari

In the fall of 2013, unusually high populations of aphids were discovered near Beaumont, Texas, 

by Dr. Mo Way. The population was soon detected along the Texas Gulf Coast and the Texas 

Lower Rio Grande Valley. The aphid soon spread and was identified in Louisiana, Mississippi 

and Oklahoma. Since it’s outbreak in grain sorghum fields, the aphid was identified 

taxonomically by Dr. Susan Halbert and other homopteran taxonomist as the sugarcane aphid, 

Melanaphis sacchari (SCA), however, this species affecting sorghum might be a new biotype 

that switched host or a new invasive strain recently introduced into the U.S. This aphid has been 

found in sorghum (both grain and forage) as well as johnsongrass (sorghum halepense) in great 

numbers successfully reproducing. In 2014, alate SCA forms were detected in fields of 

sugarcane or corn neighboring heavily infested sorghum fields in the Rio Grande Valley in South 

Texas. These SCA alates started to deposit nymphs in sugarcane or corn plants, however, 

nymphs and alates SCA vanished from these plants in two or three days.

Since widespread detection in South Texas and Louisiana in 2013, a Sugarcane Aphid Task 

Force was formed to effectively communicate and address this pest issue. The pest has since 

spread to ten states, eight of which have received Section 18 exemptions for the use of 

sulfoxaflor in sorghum. The issue is further complicated in Texas by the ongoing drought. 

Recent rains have provided some relief to farmers. However, rice farmers in the Texas Gulf 

Coast rely on water provided by lakes in the Texas Hill Country. Because of the historically low 

levels of these lakes, the farmers have been cut off from lake water for the past three years. Rice 

farmers have relied on other crops like grain sorghum, which requires much less water. This has 

increased the sorghum acreage in the Texas Gulf Coast. In 2013, over 3 million acres of 

sorghum was planted in Texas, up from a low of 1.5 million in 2011 (National Agriculture 

Statistics Service, http://quickstats.nass.usda.gov/results/F3F8C65B-0696-3C91-B805-

29F290D1B4FA). 

In South Texas, the Sugarcane aphid does not lay eggs, they are viviparous. During the winter 

months, temperatures in the South Texas only reach a minimum of around 28oF. During normal 

cold spells, the daytime temperature rises above 40oF, which does not hinder the SCA, as they 

can seek shelter in the abundance of volunteer sorghum and johnsongrass. This provides a valid 

population as sorghum acreage is planted in February in March in the southernmost areas of 

Texas. With the last harvest date of late November/early December in some areas, the 

population has a large timeframe to establish itself. The South Texas area provides an optimal 

environment for the SCA to overwinter.

The populations of SCA begin feeding on the lower leaves of sorghum plants then rapidly 

advance to the upper leaves and even colonize in the sorghum head. Mexican scientists reported

high populations of the aphid in Mexico in Rio Bravo and San Fernando in the fall of 2013. 

SECTION 166.20(b)(2): DISCUSSION OF EVENTS OR CIRCUMSTANCES WHICH 

BROUGHT ABOUT THE EMERGENCY SITUATION
Unsuccessful treatments including chlorpyrifos, methomyl and cypermethrin were applied in 

Mexico during 2013. Entire fields were lost in Mexico and Texas A&M AgriLife scientist 

feared that populations would rapidly spread northward during the 2014 growing season. That 

fear came to fruition, as the pest spread into northward into Oklahoma and southern Kansas and 

on to the Southeastern U.S. 

Natural enemies have been observed feeding on the sugarcane aphid, but they apparently had 

difficulty responding quickly enough to prevent damage. Progress is being made on developing 

resistant/tolerant sorghum lines, but sufficient quantities of agronomically acceptable cultivars 

will be years away from commercial use.

As discussed previously, it is not anticipated that there should be any anticipated risks to 

endangered or threatened species, beneficial organisms or the environment if the application is 

made according to the section 18 use directions. This is the latest list as provided by Texas Parks 

and Wildlife Department.

See Attachment H - Endangered and Threatened Species List 2011

Dr. Michael Brewer, Texas A&M AgriLife Research Specialist in Corpus Christi, has reported 

losses rangeing from 25 – 75% along the Gulf Coast. Similar yield loss has been reported 

throughout Texas. Texas A&M AgriLife Extension Specialist have confirmed SCA in most 

sorghum producing counties of Texas. Dr. Mo Way reported producers in Chambers and Liberty 

counties did not harvest their grain sorghum because the aphid damage was so severe. He also 

reported another producer in Liberty County suffered a yield loss of 50% in an infested field as 

compared to another field where the aphid did not damage the crop. Dr. Raul Villanueva 

reported two seed increase plots at the Texas A&M AgriLife Center in Weslaco were completely 

lost due to the aphid in 2013. Dr. Villanueva has also received information from Mexico that 

research plots at the Rio Bravo Agricultural Station were all devastated by this aphid and the growers 

had up to 60% loss in San Fernando and Ciudad Victoria. 

Below is the 2013 data from Texas A&M AgriLife Extension Service crop budgets.

Region Irr/dl CWT Price $/cwt $/ac $/ac w/o 

Rent

High Plains dl Income 18 9.00 162

Cost 176.18 146.18

High Plains irr Income 60 9.00 540.00

SECTION 166.20(b)(3): DISCUSSION OF ANTICIPATED RISKS TO 

ENDANGERED OR THREATENED SPECIES, BENIFICIAL ORGANISMS, OR 

THE ENVIRONMENT

SECTION 166.20(b)(4): DISCUSSION OF SIGNIFICANT ECONOMIC LOSS
Cost 572.00 472.00

Rolling Plains dl Income 22 11.10 244.20

Cost 152.53 117.53

Blacklands dl Income 45 10.00 450.00

Cost 299.73 254.85

Coastal Bend dl Income 40 10.00 400.00

Cost 302.00 190.50

The cost of production for grain sorghum is approximately $325-$375 per acre. According to the 

Texas Almanac, the avg yield of grain sorghum in Texas in 2010, 2011 and 2012 was 70, 49 and 

59 bu/acre, respectively, for a 3-year avg of approximately 59 bu/acre (56 lb/bu for grain 

sorghum) which is about 3300 lb/acre. The avg price for grain sorghum in Texas in 2010, 2011 

and 2012 was approximately $7.26, $10.40 and $11.20/cwt. The current price for grain sorghum 

is about $7.50/cwt. Also, the relatively slim profit margin means unexpected and uncontrolled 

pest infestations, like the sugarcane aphid, can have a devastating impact on the profitability of 

the crop.