UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D.C. 20460 

## NOV 30 2011

MEMORANDUM OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION

SUBJECT: Per-Acre Application Rates for Ornamental Trees inUrban Forests, Seed Treatment and Container-Grown Ornamental Uses ofPac1obutrazol FROM:

THRU:



### TO: Jonathan Becker, Ph.D., Senior Science Advisor

# ~**;W~** Biological Analysis Branch
. Biological and Economic Analysis Division (7503P) Arnet Jones, Chief Biological Analysis Branch Biological and Economic Analysis Divisio MeghanRadtke, Ph.D., Biologist Edward Odenkirchen, Ph.D., SeniorAdvisor Sujatha Sankula, Ph.D., Lead Biologist Environmental Risk Branch I Environmental Fate and Effects Division (7507P) Khue Nguyen, Chemical Review Manager Neil Anderson, Chief Risk Management and Implementation Branch 3 PesticideRe-Evaluation Division (7508P)
Peer Review Panel date: 23 November 2011 Summary BEAD provides the following high-end estimates ofthe per-acre application rate for the following uses ofpac1obutrazol based onthe label and additional information about the particular use: Ornamental trees (in urban forests)
• Tree injection

- 0.36 lbs per acre • Soil injection (around base oftrees)

- 1.91bs per acre 1• Basal drench (aroundbase oftrees) -1.91bs a.i. per acre Seed treatment
• Tomato

- 0.00040 lbs a.i. per acre • Pepper

- 0.00079 lbs a.i. per acre • Curcurbits

- 0.00029 lbs a.i. per acre Nursery production ofcontainer-grown ornamentals
• 6-inch pot, spray application

- 0.20 lb a.i. per acre • 6-inch pot, drench application

- 4.3 lb a.i. per acre • 8-inch pot, spray application

- 0.21b a.i. per acre
• . 8-inchpot, drench application

- 6.Ilb a.i. per acre • I8-inch by9-inch propagationtrays, spray application

- 0.261bs a.i. per acre 

### Background Paclobutrazol is a plant growth regulator that slows vegetative growth byinhibiting the production ofgibberellin. When gibberellin is inhibited cell division still occurs, butthe cells do not elongate resulting in a more compact plant. Additionallypaclobutrazol enhances tolerance of the plants to environmental stresses, probablythrough the increasedproduction ofabscisic acid and the phytol component ofchlorophyll (Chaney, 2005). In this document BEAD provides high-end estimates ofthe per-acre applicationrate for uses of paclobutrazol. These estimates are based on additional information about the particularuse and label information and will beused bythe Environmental Fate and Effects Division in their screening-level ecological risk assessment as part ofRegistration Review. The uses addressed herein are the application ofpaclobutrazol to ornamental trees (inurban forests), its use as a seed treatment, and its use in nursery production ofcontainer-grown ornamentals.


### Per-Acre Application Rates for Paclobutrazol Use on Ornamental Trees in Urban Forests Labels indicate that there are three application methods that canbeused when applying paclobutrazol to ornamental trees. These include injecting the active ingredient directly into the tree, injecting the active ingredient into the soil around the base ofthe tree, and drenching the soil around base ofthe tree. The labels provide information about the amount ofactive ingredient to apply pertree ofa given size. In general, the per-acre application rates for paclobutrazol use on ornamental trees inurban forests maybecalculated using the following equation: 

### Lbsai Lbsai Trees
. - T 

### * A 

### * ConversionFactors Acre ree cre The following section describes other necessary informantion (number oftrees per acre and their size) needed to complete the calculation ofthe per-acre application rate. 2Urban Forests Nowak et al. (2001) regard urban forests as ecosystems characterized bythe presence oftrees and other vegetation in association with people and their developments. Spatially, urban areas (and the contained forest) are defined bythe union ofthree census-defmed urban designations: (1) urbanized areas (populations more than 50,000); (2) places containing someurbanized areas within theirboundaries; and (3) urban places (places with more than 2,500 people located outside urban areas). Areas completely surroundedbyurban areas are included as well. As of 2001, urban areas cover more than 3.5 percent ofthe total US land areas and contain more than 75 percent ofthe US population (Nowak et al. 2001). Nowak et al. (2001 through 2011 and reference therein) conducted a series ofstudies assessing the effects and values ofurban forests in 24 cities in the United States and Canada (Table 1). As part oftheir studies they surveyed and described the forest structure in each city. The overall density (trees peracres) byland use category and the distribution oftree size by diameter at breastheight (DBH) was provided for each city. Table 1presents the reported mean density and the tree size (percent oftrees less than 6 inches in diameter) for each ofthe cities studied. A median value across all cities for these parameters was calculated for use in estimation ofperacre rates.

3Tablel. Characteristics ofTrees in Urban Forests. Mean Tree Size Density (percent Location less than 6 MostCommon Species Reference (Trees I inches

A) d.b.h)1 Atlanta, GA 111.6 NR NR Nowak et al. 2011**[A~pendix]** Baltimore, MD · 50.8 NR NR Nowak et al. 2011 [Appendix] Boston,MA 33.5 NR NR Nowak et al. 2011 [Appendix] Calgary, Alberta 66.7 NR NR Nowaket al. 2011 [Appendix] Casper, WY 9.1 57.5 Plains cottonwood, blue spruce, Nowak et al. 2010d American elm Chicago, IL 24.3 61.2 White ash, mulberry, green ash, Nowak etal. 2010a tree-of-heaven Freehold, NJ 38.3 NR NR Nowak et al. 2011 [Appendix] Jersey City, NJ 14.4 NR NR Nowak et al. 2011 [Appendix] Italian cypress, scrub oak, Los Angeles, CA 19
.9 40 laurel sumac, Mexicanfan Nowak et al. 2011 palm, Indian laurel Minneapolis, MN 26.2 47.3 Green ash, American elm, Nowak et al. 2006b boxelder Moorestown, NJ 62.1 NR NR Nowak et al. 2011 [Appendix] Morgantown, WV 119.2 NR NR Nowak etal. 2010a New Castle County, 23.9 47.6 Red maple, sweetgum, black Nowak et al. 2009 DE cherry NewYork,NY 26.4 42.7 Tree-of-heaven, black cherry, Nowaket al. 2007a sweetgum Oakville, Ontario 55.6 NR NR Nowak et al. 2011 [Appendix] Philadelphia, PA 25.1 57.5 Blackcherry, crabapple, tree- Nowak et al. 2OO7b of-heaven Sacramento area, CA 21.3 NR NR Nowaket al. 2011 [Appendix] SanFrancisco, CA 22.5 51.4 Blue gumeucalyptus, Monterey Nowak et al. 2OO7c pine, Monterey cypress Scranton, PA 116.3 77.1 Red maple, gray birch, black Nowak et al. 2010b cherry, northern red oak Syracuse, NY 54.5 NR NR Nowaket al. 2011 [Appendix] Toronto, Ontario 64.9 NR NR Nowak et al. 2011 [Appendix] Washington, DC 49.0 56.3 Americanbeech, red maple, NowaketaI. 2OO6a boxelder Wilmington, DE 18.0 54.2 Norway maple, northern white Nowak et al. 2009 cedar, tree-of-heaven Woodbridge, NJ 66.5 NR NR Nowak et al. 2011 [Appendix]
Median 35.9 54.2 (n=ll) (n=24) I 

## - - d.b.h.

- Stem diameter at breast height, measured at4.5 ft. NR

- NotReported


### Treeinjection (EPA Reg. No. 10182-90, Clipper

### TM 20 UL) Label instructions: Clipper

### TM20 ULcontains 2.51 percent pac1obutrazol (listed on label cover letter). The Pesticide Product Label System (PPLS) states that this registration has been transferred to Syngenta and is now identified as EPA Reg. No. 100-995. A label for this new 4Registration number was not located and the original draft label as the source oflabel information. EPA Reg. No. 10182-90 is a tree growth retardant for ornamental trees. Ornamental trees are usually defined as small trees with visual impact, oftenhaving a defining feature such as flowers, unique foliage, or a distinctive growth habit. Three species oftree are identified onthe label (Australian Pine, SiberianElm, and Sweet Gum) with a note that instructions for other species are being developed. Forthese three species, the label indicates that injectionholes should be drilled every 8 inches around the circumference ofthe trunk to intercept the outer sapwood and the formulation injected. The amount ofactive ingredient injected pertree varies bythe number ofinjection holes and the amount offormulation injected as described in Table 2. T bl 2 Tree SIze an

a e . d t fi 

## cr useparame ers or lpper TM20UL TreeDiameter Number of Volume of Total Volume of Total grams of (Inches) Injection Clipper 20 UU Clipper 20 UL paclobutrazol (assumed equivalent Holes per injection site per tree (ml) per tree2 toDBH)! (ml) 8 3 50 150 4.6 12 5 50 250 7.7 16 6 75 450 13.8 20 8 75 600 18.4 24 9 75 675 20.7 28 11 75 825 25.3 32 13 75 975 29.9 Source: ClipperTM20 ULlabel 1DBH= Diameter at breastheight. 2Total grams a.i. per tree = Total volume (ml) per tree 

### *Density (1.22 grams per ml [Tomlin 2003]) 

### *Percent product concentration (2.51%). Rate Calculation: To calculate a "per-acre" rate based onthese label directions, the density and sizes oftrees in the urban settings mustbeknown. Using median values for number oftrees per acre and tree diameter from Table 1, along with the maximum amount ofpaclobutrazol applied to an 8-inch diameter tree from the table above yields the following per-acre application rates:
• Per-acre application rate
- 0.36 lbs per acre

# = Total grams ai pertree (4.6 grams) 

## * Number oftrees per acre (36) 

## * Conversionfactor (l pound per453.59 grams). BEAD would characterize this estimate as a high-end value that would occur uncommonly because ofthe following reasons:
• Applications using soil injections orbasal drench around the base ofthe tree are much easier and faster to accomplish than are tree injections and are the preferred application method (Chaney 2005). • Soil injection around the base ofthe tree and basal drench also control the growth rate of grass around the tree, precluding mower and string-trimmer damage to trees as there is less need to trim close to the tree (Chaney 2005).

5• Fonnulation 10182-90 contains methanol. This has resulted in cracks, weeping injection holes and internal wood discoloration and has reduced the use ofalcohol containing products inforestry (Chaney 2005). 

### Soil Injections (aroundthetree base) (EPA Reg. No. 100-1014, Pac1obutrazoI2SC) Label instructions: Pac1obutrazol 2SC contains 2 lbs ofactive ingredientper gallon ofproduct. The label indicates thattherequired dose, calculated based ontree size and species, is to be injected 3 to 6 inches deep at 60 to 150 psi unifonnly around the tree. Tree species are divided into 6 dosage groups. Therequired dose ranges from 25 to 100 ml ofPac1obutrazol 2SC for a 6- inch (DBH) tree up to 313 to 833 ml ofPac1obutrazol2SC for a 50-inch (DBH) tree Rate Calculation: Using median values for number oftrees peracre and tree diameterfrom Appendix 1, along with the maximum amount ofpac1obutrazol applied to a 6-inch diametertree yields the following per-acre applicationrates:
• Per-acre application rate
- 1.9 lbs per acre = Amount offonnulation applied pertree (100 ml) 

## * 1 gal. fonnulation per 3785.4 ml 

## * 2lbs a.i. per 1 gal. fonnulation 

## * Number of trees per acre (36). BEAD would characterize this estimate as a high-end value because the maximum amount of active ingredientpertree is used and that many small trees inurban forests are nottreated with growthregulators.


### Basal drench (around the tree base) (EPA Reg. No. 67690-22, Profile 2SC) Label instructions: Profile 2SC is a tree growth regulator labels for the reduction oftenninal growth and pruning volume intrees not used for food production on sites such as utility rightsof-way, urban and residential environments and not-crop areas. Itis fonnulated at 2lb a.i. per gallon. Tree species listed onthe label are grouped into three application rate categories as follows:
• 1to 2 grams a.i. per inch diameter at breastheight (dbh) (example

- sweetgum) • 2 to 3 grams a.i. perinch dbh (example

- elms, maple, oaks) • 3 to 4 grams a.i. per inch dbh (example

- Bradford Pear, ash) TheProfile 2SC label states that for basal drench, the diluted spray should be applied uniformly around the tree in a shallow furrow atthepoint ofcontactbetween the soil and the tree trunk. After application, the furrow should berefilled with untreated soil. Rate Calculation: Using the maximum applicationrate listed above and the median values for number oftrees per acre and tree diameter from Appendix 1, yields the following per-acre application rates:
• Per-acre application rate
- 1.9lbs a.i. per acre = Grams ai applied perinch DBH (4) 

## * Median DBH (6) 

## * 1poundper453.59 grams 

## * Number oftrees per acre (36).

6BEAD would characterize this estimate as a high-end value as is described in the soil injection use above.


### Per-Acre Application Rates for Paclobutrazol Use as a Seed Treatment Paclobutrazol2SC maybe applied to tomato, pepper, and cucurbit seeds using a variety of methods (e.g., slurrys, film coatings). The label reports the amount ofactive ingredient' to be applied per seed and the seeding rate per acre mustbeknown to calculate a per-acre application rate. 

### Seed Treatment (tomato, pepper,cucurbit) (EPA Reg. No. 100-1014, Paclobutrazol2SC) Label instructions: Paclobutrazol 2SC contains 2 lbs ofactive ingredientper gallon ofproduct. Paclobutrazol 2SC maybe applied to tomato, pepper, and cucurbit seeds using a variety of procedures using slurrys, film coatings, and direct application. The treated seeds are then direct seeded or used to produce transplants. The following rates are used:

• Tomato - 1to 12.5 micrograms a.i. per seed • Pepper -1 to 16 micrograms a.i. per seed • Crncurbits - 1to 6.5 micrograms a.i. per seed
Rate Calculation: Becker and Ratnayake (2011) provide seeding rates (seeds per acre) for these three crops as shown in the calculations below. The per-acre application rate may be calculated by following formula: 

### lbs a. i.



### Acre ug a. i. 1

### pound a. i. 

### Seed or 

### transplants



### -**~---** 

### x x ---------------- seed 453,592,370 

### ug a. i. 

### Acre Using the mean seeding rates for these three crops from Becker and Ratnayake (2011), the following rates are calculated:

• Tomato

- 0.00040 lbs a.i. per acre = (12.5 flg a.i. per seed 

## * 1 lb a.i. per453,592,370 flg a.i. 

## * 14,400 seeds per acre) • Pepper

- 0.00079 lbs a.i. per acre

# = (16 flg a.i. per seed 

## * 1 lb a.i. per 453,592,370 flg a.i. 

## *22,400 seeds per acre) • Curcurbits

- 0.00029 lbs a.i. per acre = (6.5 flg a.i. per seed 

## * 1 lb a.i. per453,592,370 flg a.i. 

## *20,200 seeds per acre)
BEAD characterizes theses results as high-end values for the following reasons:
• Maximum application rate per seed is used for all three crops.

7• Includes planting densities across the US for all end uses ofthe crop. Often crops intendedfor processing are planted athigher densities than that intended for fresh markets
. • Therange ofthe number ofseeds per acre given inBecker and Ratnayake (20011) is upwardlybiased because the presented values are based on the minimum row width and the maximum number ofseeds per row foot. Growerplantto an overall density per-acre based on local conditions and experience, so as therow width shrinks, typically the distance between seeds increases (and visa versa). • In the case ofcurcurbits, onlythe seeding rates for cucumbers and summer squash were consideredhere. Ifpumpkins and melons were to be included the mean number ofseeds per acre would be substantially lower as these crops have more widely spaced plantings.


### Per-AcreApplication Rates for Paclobutrazol Use on Nursery Grown Ornamentals
The equivalent per-acre application rates may be calculated using the following general equation:

Lb 

### a. i. Acre Oz. Spray 

### 1 Gal. Spray Oz. Formulation 

### 1 Gal. Formulation



### -**----~.~-** 

### x x ------------- x**------~--~----** Contazner 

### 128 oz. Spray Gal. Spray 

### 128 oz. Formulation 1.0 gm a. 

### i. 1 lb a. i. Containers 

### x x x --------- Gal. Formulation 

### 453.59 gm a. i. Acre BEAD based the per-acre applicationrate estimates on the following assumptions, which when taken together, result in a reasonable high-end screening estimate:
• The treatment ofcontainer-grownplants occurs inthe greenhouse at the maximum label applicationrate. • Once moved to outdoor plant beds all ofthe active ingredient is assumed to remain available for off-site transport. This is a very conservative assumption as ancymidol (ARestTM, AbideTM) is rapidly absorbed bythe plant, and plants either sprayed or drenched with this chemical canbe watered as soon as 1hour after application withoutreduction in efficacy. In comparison other PGRs, such as daminozide (B-NineTM) are absorbed more slowly, requiring 4 hours for complete absorption (Bailey and Whipker, 1998). • Containers are placed outdoors in plantbeds at the highest density possible while allowing for normal nursery operations (such as irrigation, fertilization, scouting, etc.). Thehighest density possible is termed "cantight" in the nursery industry. • Thelayout ofthe nursery is typical for operations producing container-grown ornamentals.


### Soil drench andbench sprays (potted ornamentals) (EPA Reg
. No
. 100-1079, Bonzi® II) Label instructions: Bonzi® II contains 0.036 grams active ingredientperfluid ounce ofproduct. Bonzi® II maybe applied as either a spray or as a drench. To make a spray or drench solution for a specific ornamental species, the user prepares the solution to be applied based onthe concentration needed (e.g., 1fluid ounce offormulated product mixed with a gallon ofwater will 8produce a 10 ppm solution) and determines the amount to apply based on the method of application (foliar spray or drench), plant species being treated, and the size ofthe potcontaining the plant. Table 3 identifies the types ofornamentals specified on the Bonzi® II label and the recommended concentrations. Table 3. Types ofornamentals and recommended concentrations on the Bonzi® II label. PlantType Cone. OfSpray (ppm) Cone. OfDrench BEADComments (ppm) , Azaleas (Florist) toO to 200ppm 5 to 15 ppm Bedding Plants 5 to 90ppm 1ppm Usually moved from greenhouse directly to retail sales. BeddingPlantPlugs 1to 20ppm Not recommended Bulb Crops "leastdesirable method" 5 to 200 ppm Usually moved from greenhouse directly to retail sales. Pot Chrysanthemums 50to 200ppm 1to 4 ppm Flowering and Foliage 30to 50ppm 1to 2 ppm Plants Geraniums toto 30ppm "make with caution" Hibiscus 30to 150ppm 4 ppm Poinsettias to to 30ppm (15 to 45 2 to 4 ppm Usually moved from greenhouse ppm inFL) directly to retail sales. WoodyLandscapePlants 100ppm 4 ppm

Rate Calculation:
• Bench Sprays

- Plants in containers are places as closely as possible onthe bench and 2 to 3 quarts ofspray volume per 100 square feet is applied. Fourhundred 6-inch diameter containers canbe packed onto a 100 square foot bench (5 

### ft. by 20 

### ft.). Approximately 79 percent ofthe applied spray will be deposited in the containers (area ofcontainers [400*1t*i (78.5 sq. 

### ft.) -:- area sprayed (100 sq. 

### ft.) =78.53 percent]. This produces an application volumeper 6-inch container of0.188 fluid ounce perpot (0.785 

## * 3 quarts sprayper 100 square feet 

## * 32 fluid ounces per quart 

## * 100 square feet per400 pots). Similarly, assuming that 224 8-inch containers canbeplaced on a 100 square foot bench (4 

### ft. by 25 

### ft.), the application volume per 8-inch container is 0.337 fluid ounces perpot. Finally, assuming that 88 linertrays maybeplaced on a 100 square foot bench, the application volumepertray is 1.1 fluid ounces (3 quarts sprayper 100 square feet 

## * 32 fluid ounces per quart 

## * 100 square feet per 88 trays) [All ofthe applied spray is assumed to be**d~posited** inthe tray containers]

• Drenches

- The label includes a table ofvolumes based onthe size ofthe containerto be applied to each pot. For example, 4 fluid ounces is applied to a 6-inch pot and 10fluid ounces is applied to an 8-inch pot.
Size ofcontainers: Although the American Nursery and Landscape Association (ANLA, 2004) has done much to standardize the nomenclature for the sizes ofcontainers used in ornamental productions, considerable variability remains. Forexample, a "#1" containeris specified to 9containbetween 152 and 251 cubic inches (0.65 to 1.08 gallons) byANLA (2004). Dimensions ofa #1 container vary, with top diameters ranging from 6 inches to 8 inches. "Azaleapots" contain 132 cubic inches and typically measure 5718 (diameter) by4718 inches (height). The dimensions ofpropagation liner trays are 18 3/8 (W) x 9 3/16 and contain either 18 (i.e., 3 x 6) or 32 (i.e., 4 x 8) square cavities (Nursery Supplies 2011). Approximately 88 trays canbeplaced on a 100 square foot bench (6 feet x 16213 feet). Container Nursery Layout: Typical production areas are designed to allow for the orderly movement ofplants into and out ofthe areas byworkers and to allow access for the care ofthese plants. Yeager and Ingram (2010) describe typical production areas for nurseries. These areas all have plantbeds that are 8 feet wide separated by 2 foot Walkways. Equipment access is provided by a narrow road (10 to 20 feet wide) every 100 feet between the plantbeds and by a 30-foot wideperimeter road. This layoutresults in the production area with approximately 50 % ofthe area consisting ofplantbeds, with the remaining area in service roads and access paths. Forthe operation as a whole, this estimate does not account for propagation areas, mediapreparation and storage areas, service areas (equipment storage and repair facilities, chemical storage areas, offices), employee facilities, and shipping areas. It should be noted that these typical dimensions are often modified based onlocal conditions. Estimates ofthe per-acre number ofcontainers: Based onthe layout described by Yeager and Ingram (2010) and assuming thehighest density possible ("can tight") of6-inch containers (i.e., 4 per square foot) in the plantbed area (50 percent ofthe total area), the overall density is 87,120 containers per acre. Using 8-inch containers, the overall density wouldbe about 49,000 containers per acre. Using 18-inchby9-inchtrays, the overall density would be about 19,360 trays per acre (43,560 squarefeet per acre 

## * 50% in plantbeds 

## * 1tray per 1.125 square feet). Each lO-inch x 20-inch seeding tray has a surface area of200 square inches (=1.389 square feet and overall density would be 15,680 trays per acre (43,560 square feet per acre 

## * 50% inplant beds 

## * 1tray per 1.389 square feet). Robbins (no date), in his discussion on starting a wholesale nursery, estimated that the average number ofcontainers per acre, including the requirements for roads, aisles, and buildings in the operation is 110,000to 130,000 I-gal containers I Acre. Hinson et al. (2011) in their study of estimating the cost ofproducing selected ornamental crops used 30,000 plants per acre (azaleas in one-gallon container) as the estimate ofthenumber ofplants in a high density production scenario. Neither author provided a basis for the number ofcontainers per acre. Thesethree studies support densities ranging from 30,000 to 130,000#1 containers per-acre. The large ranges ofthese values reflect the variability in nursery layoutbased onlocal and regional conditions and as well as the variability in the sizes ofnursery containers as described above. BEAD recommends using values of 87,120 (6-inch container), 49,000 (8-inch container), and 19,360 (9-inch x 18-inchpropagation tray) for calculation ofper-acre applicationrates. Equivalent per-acre application rates: Using the equationpresented earlier and assuming a "cantight" number ofcontainers per acre and the maximum application rates, the equivalent per-acre application rates are: • 6-inch pot, spray application

- 0.20 lb a.i. per acre = (0.188 oz. sprayper 6-inch container 

## * 1 gal. sprayper 128 oz. spray 

## *20 oz. formulation per gallon spray

## * Igal. formulation 10per 128 oz. fonnulation 

## *4.608 grams a.i. per gal fonnulation 

## * 1poundper453.59 grams 

## * 87,120 6-inch contaiI.lers per acre). • 6-inchpot, drench application

- 4.3 lb a.i. per acre = (4 oz. drench per 6-inch container 

## * 1 gal. sprayper 128 oz. spray 

## *20 oz. fonnulation per gallon spray 

## * 1 gal. fonnulation per 128 oz. fonnulation 

## *4.608 grams per gal. fonnulation 

## * 1pound per453.59 grams 

## * 87,120 6-inch containers per acre). • 8-inch pot, spray application

- 0.2 lb a.i. per acre

# = (0.337 oz. spray per 8-inch container 

## * 1 gal. sprayper 128 oz. spray 

## *20 oz. fonnulation per gallon spray 

## * 1 gal. fonnulation per 128 oz. fonnulation 

## *4.608 grams per gal. fonnulation 

## * 1poundper453.59 grams 

## * 49,000 8-inch containers per acre). • 8-inch pot, drench application

- 6.11b a.i. per acre 

### = (10 oz. drench per 8-inch container 

## * 1 gal sprayper 128 oz. spray 

## * 20 oz. fonnulation per gallon spray 

## * 1 gal. fonnulation per 128 oz. fonnulation 

## *4.608 grams per gal. fonnulation 

## * 1poundper453.59 grams 

## * 49,000 8-inch containers per acre). • 18-inch by 9-inch propagation trays, spray application

- 0.261bs a.i. per acre = (1.1 oz. spray per 18-inchby9-inch tray 

## * 1 gal. sprayper 128 oz. spray 

## *20 oz. fonnulation per gallon spray 

## * 1 gal. fonnulation per 128 oz. fonnulation 

## *4.608 grams per gal. fonnulation 

## * 1pound per453.59 grams 

## * 19,360 18-inch by 9-inch trays per acre). BEAD characterizes these application rates as high-end values because oftheuse ofmaximum application rate per container and highest density ofcontainers in the plantbeds. 

### Pre-plantplug 

### I liner soak andPre-plantbulb soaks (EPA Reg. No. 400-515, Paczol®) Label instructions: The label for Paczol® contains instructions for the pre-plant application for plugs, liners andbulbs as a soak. Specific use rates are not given for this method becausethe rate is influencedbyvarying soak times, the extent ofrooting ofeach plant, the media moisture levels, the differing sensitivities ofcultivars and species being treated, cultural practices and environmental factors. BEAD does nothave infonnationto be able to calculate a per-container application rates and therefore cannot calculate an equivalent per-acre application rate. However, the equivalent per-acre applicationrate for this application method should be encompassed bythat calculated for the soil drench orbench spray applications to container grown ornamentals. The Paczol® label states under "Detennining OptimumRates" that the rates recommended are ranges and should be used only as a guideline. This is followed bythe statement "Do not exceed the maximum recommended rate". Since the calculation ofthe application rate for the soil drench and bench spray application methods for container grown ornamanetals use the maximum applicationrate, the soak application method will not exceed this rate. Further, the pre-plant soak method for treatment ofplug/ liners and bulbs are most frequently used when preparing containers for the retail market. Itwould be unusual for these containers to be placed on outside plantbeds priorto their shipment.

11References ANLA. 2004. American Standard for Nursery Stock. American Nursery and Landscape Association. ANSI Z60.1-2004. Bailey, D.A. and B.E. Whipker. 1998. Best Management Practices for Plant Growth Regulators Used in Floriculture. Horticulture Information Leaflet

### # 529. North Carolina Cooperative Extension Service. Becker, J. and S. Ratnayake. 2011. Acres PlantedperDay and Seeding Rates ofCrops Grown in the United States. Memo to P. Deschamp, Health Effects Division and D. Spatz, Environmental Fate and Effects Division, Office ofPesticidePrograms. Chaney, W.R. 2005. Growth Retardants: A Promising Tool for Managing Urban Trees. PurdueUniversity Extension. FNR-252-W. Hinson, R.A., R.D. Little, K.E. Hood, A. Owings, R. Harkess, and J. Black. 2011. Estimating the Cost ofProducing Selected Ornamental Crops in Plant Hardiness Zones 8 and 9. Journal ofthe American Society ofFarmManagers and Rural Appraisers, Vol. 74, No.1, Pg.3-22. Latimer, J.G. 2009. Selecting and Using Plant Growth Regulators onFloricultural Crops. Publication430. Virginia CooperativeExtension, Virginia Tech, Blacksburg, VA. Nowak, D.J., M.H. Noble, S.M. Sisinni, and J.F. Dwyer. 2001. People & trees: assessing the US urban forest resource. Journal ofForestry 99(3): 37-42. Nowak, DJ., R.E. Hoehn III, D.E. Crane, J.C. Stevens and 

### c.L. Fisher. 201Oa. Assessing urban forest effects and values, Chicago's urban forest. United States Department of Agriculture, Forest Service, Northern Research Station Resource Bulletin NRS-37. Nowak, DJ., R.E. Hoehn III, D.E. Crane, J.C. Stevens and J.T. Walton. 2006a. Assessing urban forest effects and values, Washington, D.C.'s urban forest. United States Department of Agriculture, Forest Service, Northern Research Station Resource BulletinNRS-1. Nowak, DJ., R.E. Hoehn III, D.E. Crane, J.C. Stevens and J.T. Walton. 2007a. Assessing urban forest effects and values, New York City'S urban forest United States Department of Agriculture, Forest Service, Northern Research Station Resource Bulletin NRS-9. Nowak, DJ., R.E. Hoehn III, D.E. Crane, J.C. Stevens and J.T. Walton. 2007b. Assessing urban forest effects and values, Philladelphia's urban forest United States Department of Agriculture, Forest Service, Northern Research StationResource Bulletin NRS-7. Nowak, D.J., R.E. Hoehn III, D.E. Crane, J.C. Stevens and J.T. Walton. 2007c. Assessing urban forest effects·and values, SanFrancisco's urban forest United States Department of Agriculture, Forest Service, Northern Research StationResource Bulletin NRS-8. Nowak, D.J., R.E. Hoehn III, D.E. Crane, J.C. Stevens and J.T. Walton. 2007d. Assessing urban forest effects and values, Casper's urban forest United States Department ofAgriCUlture, Forest Service, Northern Research StationResource Bulletin NRS-4. Nowak, D.J., R.E. Hoehn III, D.E. Crane, J.C. Stevens and V. Cotrone. 201Ob. Assessing urban forest effects and values, Scranton's urban forest. United States Department of Agriculture, Forest Service, Northern Research Station Resource Bulletin NRS-43. Nowak, D.J., R.E. Hoehn III, D.E. Crane, J.C. Stevens, J.T. Walton, J. Bond and G. Ina. 2006b. Assessing urban forest effects and values, Minneapolis' urban forest United States Department ofAgriculture, Forest Service, Northern Research StationResource Bulletin NE-166.

12Nowak, DJ., R.E. Hoehn III, D.E. Crane, L. Weller and A. Davila. 2011. Assessing urban forest effects and values, Los Angeles' urban forest. United States Department ofAgriculture, Forest Service, Northern Research StationResource Bulletin NRS-47. Nowak, D.J., R.E. Hoehn III, J. Wang, A. Lee, V. Krishnamurthy and G. Schwetz. 2009. Urban forest assessment in northern Deleware. United States Department ofAgriculture, Forest Service, Northern Research StationResource Bulletin NRS-33. Nursery Supply, Inc. 2011. Nursery Supplies Catalog. Robbins, J.A. No date. Nursery Series. Starting a Wholesale Nursery

- Part II. University of Arkansas CooperativeExtension Service, University ofArkansas Agriculture and Natural Resources. Publication Number FSA 6056. Tomlin, C.D.S. [Ed.]. 2003. The Pesticide Manual, 13th Edition. British Crop Protection Council. 1344 pages. Yeager, T.H. and D. L. Ingram. 2010. Layout and Design Considerations for a Wholesale Container Nursery. CIR558, Environmental Horticulture Department, Florida Cooperative Extension Service, Institute ofFood and Agricultural Sciences, University ofFlorida.

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