UNITED ST ATES ENVIRONMENTAL PROTECTION AGENCY WASH IN GTO N D . C . , 20460 

## DEC 2 2 2015 OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION 

### MEMORANDUM SUBJECT: BEAD Chem ical Profile (BCP) for Registration Review: Uniconazole 

### (128976) FROM:

THRU:

TO: Leonard Yourman , Plant Pathologist 

## I 

# j Biological Analysis Branch

## /V**~** Don Atwood , Entomologist Science Information and Analysis Branch 

### Andrew Lee , Economist {).

# j 

# C

# h Economic Anal y sis Branch 

# 'tf Biological and Economic Analysis Division**(750 '-"** **;.._.,-~** Mark Suare z, Actin g Chief Biological Analysis Branch Diann Sims, Ch ie f 

# U\**,JYY'rl#~~** Science Information and Analysis Branch Timothy Kiely , Ch ief

# ·AA ' \) Economic Analysis Branch 

## v- \.

## ~ Biological and Economic Analysis ·vision 

### (7503P) Susan Bartow , Chemical Review Manager Risk Management and Implementation Branch l V Pesticide Re-evaluation Division 

### (7508P) Product Review Panel: December 9, 2015 

### SUMMARY Uniconazo l e is a growth regulator that is used on herbaceous ornan1ental plants to reduce shoot and stem elongation to provide consumers with compact and uniform transplants for placement in plant beds , gardens , and other ornamental l ocations. S imilarl y , uniconazole i s registered for use on fruiting vegetable transplants to produce compact tomatoes , peppers , and eggplant for sal e to consumers. 

### It can be used as a fol iar spray , bulb dip o r substrate drench (Currey and Lopez , 20 I 0) . U niconazole is a triazol e c hemical related to the more widely used plant growthregulator , paclobutrazo l. U niconazole , like paclobutrazo l. inhibit s g ibb erell ic ac id sy nthe sis and thu s re duc es see d germ in ation and s tem and s hoot elongat io n (A rn o ld and McDonald , 2001) . 

### U

nic o nazo l e is effec ti ve on a wide range of ornamental sp ec i es . w hi ch is one of the reasons it ha s been imp o rt ant fo r propagators of various pl ant s pecies. According to publicly available dat a (NASS, 200 7 ) uniconazo le is used to vary ing degrees in th e nursery propagat ion industry ; u se appears to va r y according to the cro p grown and location of the nursery. Fo r exa mple , a large numb er of Texas woody ornamental & v ine o perati o n s u se bo th uniconazole and paclobutrazol , w h ile paclobutrazoL no t uni conazole, is u sed w idely by Texas nur sery propagation operations. In ge ne ra l , w hil e p aclo butrazo l appears to be more w id e ly u sed th a n uniconazole. uniconazo le pro vid es plant propagators w ith a highl y active growth regulato r th a t re s ult s in compact and uniform tran sp lant s characte ri stics that are necessary for marketab ilit y a nd consumer acceptance. 

### I NTRO DUCTI ON FIFRA Sec ti o n 3(g) mandates that EPA periodic a l ly r ev ie w th e reg is trati o n s of all pesticides to in s ure th at th ey do not pose unreasonable adverse effects to human hea lth and the environment. This p eri o dic r ev iew is necessa ry in light of sc ient ifi c advancemen ts. chan ges in policy , and change s in u se pattern s that may alter th e conditions underpinnin g previous registration deci s ions. ln de terminin g w hether effects are unrea so nabl e. F IF RA require s that the Agency conside r th e ri sks a nd benefits of any use of the pesticide. The B io log ic a l and Eco nomic A nal ys i s Di vis ion ( B EAD) C hemical Profile ( BCP) provides a brief overv ie w of th e p est management roles fo r uni conazo le. Howeve r. BEAD does not have current u sage data for uniconazole and does not have a lab e l data report. The in fo rmation provided in this BEAD C he mical Profile ( B CP) m ay be used by s takeholders (e.g., users and re g is tra nt s). OPP ri s k and be ne fit assessors , and OPP ri s k managers. and th e ge neral public durin g the R eg is tra tion Review process of this pes ticide . 

### AGRI CU LTURAL USE SITES Un ico nazole ca n be u sed for production of fruitin g vegetab le tran s p lant s including tomato , pepper , and eggp lant in g reenhouses, shadehouses , or lathh o u ses. T hi s u se r es ult s in mo r e co mp ac t tran s plants that result in high den si ty producti o n plantin gs and more marketable tran s plants to consume rs. 

### NON-AG RI CULT URAL USE S ITES Use s ites a r e ornamental p lants grown in commercial g re enho u ses. g lass houses, lathhouses , and shade s tru ctures (w he r e plants are grown in containers). Li s t ed pl ant s include annual and perennial bedding plan ts . bulbs (dip ) , woody land scape ornamenta ls. Eas ter lil y , Poinsen ia , and others.

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### FORMULATIONS AND APPLICAT IO N METHODS Uniconazole may be applied to plant shoots or roots as fo li ar sprays , substrate drenches , liner dips , and media sprays (Currey and Lopez, 20 1 0) . Foliar sprays are the most common but spray volume (to runo ff) can vary among applicato rs compromising uniformity. One strategy has been the application of a specific volume per area (e.g . , Currey and Lopez , 20 I 0 - two quarts spray so lution per 100 sq ft). 

### H I ST ORY OF BEAD ASSESSMENTS A search of the BEAD database indi cates that BEAD has not conducted benefits or impact assessments for uniconazole. In 2007 , BEAD reviewed a Section 18 Emergency Exe mption request for use of this chemical on transp lant tomatoes in greenhouses to control excess ive growth . BEAD determined that the situation appeared to be a chronic problem rather than an emergency. However , the need for a material to produce more marketable compact plants is exemplified by the subsequent Section 3 l abeling of uniconazole for use in the production of fruiting vegetable transplants. 

### USAGE Uniconazole is effective on a wide variety of plant species . Use rates depend on the ornamental species of interest. For growth control, some bedding plants may receive a single spray of 1-2 ppm, wh il e more aggressive plants (e . g . , petunia o r marigold) may require higher rates (4-6 ppm) (Runkle, 2011). Fast growing perennials such as gaura , li atris, and phlox may require rates of 10-15 ppm. These rate s (for Michigan) may be lower than rates necessary in warmer locations. Depending on the plant and use rates , the reduction of stem elongation ma y last for 3-5 weeks or longer. Uniconazole is absorbed most effecti vely by the plant stem. App lic ation timing is critical and applicati on is typically 7-10 days after transp l ant of plugs and cuttings. The effect on stem elongation is usually obse r ved seven to ten days after application (Runkle, 2011 ) . According to NASS data (NASS , 2007) use rates may range from approximately 0.00 I to 0.044 lb per acre (for bedding p l ants) , with an average of 0.01 lb per acre for all nursery operations. Table 1 summarizes NASS data that provides the percent of nursery operations that use uniconazole. For compari son, data for the similar and most widely used growth regulator , paclobutrazol , is a lso prov ided . Only a few (program) states were indicated in the summary and therefore , nursery use nationwide may not be accurately reflected. Data were not available for all nursery operations. Nevertheless, th e data indicate a wide range of use by nursery operators- a large number of Texas woody ornamental & 

### vine operations use both uniconazole and paclobutrazol , while paclobutrazo l , not uniconazo le, is use d widely by Texas nursery propagation operations. In general, paclobutrazol appears to be more wide ly used than uniconazole.

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### Tab le 1. Summary 1 of Percent of Nursery Operations Using Uniconazole and Paclobutrazol (2006) Pr o!!ra m Sta t es CA I F L M l 

### I OR 

### 1 PA 

### 1 TX 

### 1 I 

### I I I I Percent of All Nursery & Floriculture Op erations Us ing A.I. Uniconazole 4 

### I -- 8 

### I I 

### I 2 

### I 5 

### I Paclobutrazol 8 

### I 

## -- 18 

### I I - r 10 

### I 6 

### I Percent of All Nursery Operations Using A. I. Uniconazole I 

### I
-- -- 

### I 

## -- I 

## -- I 8 

### I Paclobutrazol 2 

### I I I 

### I 

## -- l
-- 

## - , 8 

### I Percent of Nursery Propagation Operations Using A. I. U

niconazole 3 

### I -- 

## -- I 

## -- I
-- 

## l 5 

## l Paclobutrazol 6 

### I 

## -- -- 

### I -- 

### l 

## -- 1 51 

## -, Percent of Deciduous Shrub Operations Using A.I. Uniconazole -- 

### I -- 

## -- I -- I -- 

### I 44 

### I Paclobutrazol 

## -- I -- -- 

### I 

### -- 

### l 

## -- l
-- 

## -, Percent of Other Woody Ornamental & Vin e Operations Us ing A.I. Uniconazole 

## -- I I 

## -- I 

## -- I 9 

### l 47 

### l Paclobutrazol 6 

### I 4 

### -- 

### I 

## -- I 

## -- I 47 

### I Percent of All Floriculture Ooerations Using A.I. Uniconazole 5 

### I
-- 16 

### I .., -' 

### I .., -' 

### I 10 

### I Paclobutrazo l II 

### I 2 34 

### I 6 

### I 21 

### l II 

### -, Percent of Flowering Plant Operations Using A.I. Uniconazole 7 

### I 2 10 

### I 4 

### I 4 

### I 13 

### I Pac lobutrazol 11 

### I 7 17 

### I 12 

### I 23 

### I 15 

### I Percent of Bedding Plant Operations Using A.I. Unico nazole 16 

### I -- 19 

### I 5 

### I 2 

### l 1 1 

### l Pac lobutrazol 30 

### I 19 39 

### I 9 

### I 20 

### I 11 

### I Percent of Foliage Ooerations Using A.I. U

niconazole 2 

### I -- 14 

### I -- 

### I -- 

### I
-- 

### I Paclobutrazol 2 

### I ..,.., 

### I I 5 

### 1 2 

### l
-- -'-' 

## -- Percent of Floriculture Operations Using A.I. Uniconazole 

### -- 

### I 

## -- 10 

### I
-- 

### I
-- 

### I
-- 

### I Paclobutrazol 12 

### I 18 10 

### I -- I 10 

### I 

## -- l Percent of Herbaceou s Per e nnial Operations Using A.I. Uniconazole 5 

### I -- 9 

## I 3 

### I
-- 

# -, -- 

### I Paclobutrazol 5 I 

## -- 14 

### I 3 

### I 8 

### I 2 I 1 Agricultural Chemical Usage 2006 Nursery and Floricultur e Summary. December 2007. USDA National Agricultural Statistics Service (NASS). T ota l

.., -' 7 I I I 9 8



### -- 5 8 6 14 7 15 II 24

1 2 2 7 2 6 http: //usda .mannl ib .comel l.edu/usda/nass/AgriChem UsN ursF l o//2000s/2007 IAgriChem UsNursFlo - 12 - 19-2007 .pdf (--)Indicates that the infom1ation was not published by NASS. 

### RO LE OF UN IC ONA Z O L E Uniconazole is a growth regulator that can be used as a foliar spray , bulb dip or substrate drench (C urrey and Lopez , 2010). 

### It is a triazole chemical related to the most w i de ly used plant growth regulator , paclobutrazol , but up to five times more active on a ppm basis. Uniconazole can be applied as a drench at rates 50% l ower than those used for paclobutrazo l (Whipker , 

### 2013) . Un iconazole, like paclobutrazol , inh ibits g ibberellic acid synthesis and thus reduces stem and shoot elongation (Arnold and McDonald , 2001). Uniconazole does not readily move within the 4plant since they are transported in the xylem and not the phloem (Whipker. 2013). As a result uniconazole (as well as paclobutrazol) is absorbed by the leaves, but is not readily transported out to other parts of the plant. Uniconazole is t ypically used on a w id e range of herbaceous ornamental plants to reduce plant height, which is important in order to provide compact and uniform plants with optima l aesthetic appeal to the e nd-u se r. In addition, a seco ndary effect of unicon azo le (and other g ibb erellic acid re g ulators) is an increase in chlorophyll production creating greener leaves (W hipker , 2013). These attr ibutes indicate benefits fo r both the g r ower and consumer. It is among the most active and persistent plant growth regulators. Rates are determined by the type of plant and the length of time that the growth reduction effect is desired. Excessive persistence of the growth regulator is not considered desirable once the plant is sold to the co n sumer (Latimer et al.. 2003). 

### INFORMATION THAT MAY BE USEFUL FOR BEAD'S FUTURE WORK I f ri sks are identified for uniconazole a benefits or impact assessment may be necessary to weigh risk and benefits. BEAD data presented in this memo were obtained from a publicly available survey that was conducted in 2006 (NASS, 2007). Therefore, updated information on the use of uniconazole would be necessary to indicate its role in nursery and transplant management. I n addition , the relative importance of uniconazole (in compariso n with widely used alternatives. such as paclobutrazol) will enab le an assessment of the value and benefits of uniconazole to growers and consumers. 

### REFERENCES Arnold, M.A. and McDonald, G. V. 2001. Paclobutrazol and uniconazole applications affect production quality and subsequent landscape performance of blue Plumbago. http ://wv.rw . plantanswers . com / research blue plumbago . htm Currey, C. J. and Lopez. R. G. 20 l 0. Applying plant growth retardants for height control. Commercial Greenhouse a nd Nursery Production . Purdue University Extens io n Pub!. H0-248- W. https ://www . exten s ion . purdue . edu/extmedi a/ HO/ H0 - 248 - W . pdf EP A 2007. Office of Pesticide Program s. Biological and Eco nomic Analysis Division. "Review of a Request for Emergency Exemption of Uniconazo le -p in Alabama fo r Use on Transplant Tomatoes in Greenhouses to Co nt ro l Excessive Growth. (07-AL-0 1) (D335047). Latimer, J . G., Scoggins , H. 

### L., and Banko, T. J. 2003. Persistence of plant growth regulator effects on perennial plants in the nursery. Proc. XXVl Internat ional Horticultural Congre ss (IHC), Acta Hort. 624: 229-232. http ://www . hort.vt.edu/lloriculturc/ documents/VT 2003 Persistence of Plant Growth Regulat or Effe c ts on Perennial Plants in the Nursery Acta! 1011 624 p229 232 . pdf NASS. 2007. Nursery and Floriculture Chemical Usage Data, 2006. USDA National Agricultural Statistics Service (NASS). December 2007. 5http :/ /usda . mannlib . cornel l . edu/usda/nass / Ag riCh emUsNursFlo//2000s / 2007/ AgriChemUsNursF l o - 12-19 - 2007 .pdf Runkle , E. 2011 . Tip s on u s in g uniconazole. Greenho u se Product News . Apr il 13 , 20 11. http : //v.'WW .g pnmag.com/ tips - u s ing - uniconazo le Whipker , B. E. 2013. Pl an t growth re gu lator g uide. Grower Talk s Magaz ine . http ://www.ballpub li shing.com / pdf/PGR G U ID E 20 13-LowRcz .pdf

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