UNITED STATES ENVIRONMENTAL PROTECTION AGEN CY WASHINGT O N , D
. C
. 20460 

### MAY 

## 192015

OFFICE O F CHEMICAL SAFETY AND POLLU T IO N P REVENTION 

### MEMORANDUM 

### SU BJECT:
FROM:



### THRU :

TO : Qualitative Assessment of Daminozide Use in Ornamental Pl ant Product ion (DP# 426348) (PC Code 03510 I) Suni l Ratnayak e, Biologist, (

# 1~,

# 1**~** Bi olog ica l Analysis Branch Stephen Smearman , Economist 

## J..J- _J. A
. 

### J
...... Economic Analysis Branch

### ~**~** Biological and Economic Analys is Division (7503P)

# ~ Arnet Jones, Chief**~** 

### Bio logical Ana lysis

# Branc**~** . Timothy Kiely, Chief 

# n**~** Eco nomic Analysis Branch 

### '\J 

# J Bi o logical and Economic Analysis Division (75 ) 

### Margaret Ha thaway, Chemical Review Manager Pesticide Re

- eva luation Division (7508 P ) 

### Peer Review Panel date: Apr il 15 , 2015 SUM MARY Daminozide i s a systemic plant growth regulato r (PGR) registered in 1963 for use in ornamental plant production. (USEP A, 1993). Damin ozide is used mostl y on containerized ornamenta l plants grown in commercial o r re search green houses and nurseri es. Application of daminozide inhibits the syn the sis of gibbe rellic acid in p lants. Ac ti vity of daminozide shortens the internode leng th of ornamental plants, reduces plant hei g ht , and g ives a short and compact appearance. Cur r e ntly , there are no r eg is te r ed food uses.

Page I

### I N TROD UC TIO N As a part of the reg i stration review process , thi s brief benefits overv iew provides information needed for risk manageme n t. I n particular, it conside rs the risks and benefits of t he u se of daminozide
. 

### USE SIT ES Cu rr e ntl y, daminozid e is registered for use in nur se r ie s, shadehouses, and greenhous es. 

### A PPLI C ATIO N O F D AM I N O ZID E Daminozide is app l ied as a spray on the fo li age of ornamental plants grown in commerc i a l or re s earch greenhouse s and nurse ri es. It i s a lso app l ied as a drench (application of the so l ution to grow ing substrate). Spraying is d irected at th e leaves and stems to th e point of run-off or until leaves look saturated. Ap pl ication rate s are dependent on the crop being treated and desired leve l of plant size. Generally , daminozid e is app li ed inside of g reenhouses , so there is little or n o potential for off

- s ite drift. Daminozide red uc es the internode length of ornamental plants by inhibiting the sy nth esis of g ibb e rellic acid. 

### B E N EF IT S OF US I NG DAMI NOZID E Co ntrolling plant s i ze i s an important aspect of g ree nh o u se plant production. Daminozide has a particular niche use on ornam e ntal plant s which i s for reducing plant s ize. Re duction of plant size maximizes production of ornamental plants per unit area of a g reen house. Also , it impro ves the efficie nc y of certa in g r ee nh o u se activities such as irri gation , fertilization , and handling. In addi tion , the redu c ti o n of interrnodal length minimi zes plant damage during s hippin g and h and ling and help s to produce more visually pl eas in g compact plants with deeper g reen coloration
. Co mpared to the many othe r p lant growth re g u lators, daminoz i de ha s a fairly short residual effec t , typically la st in g one to four weeks d e p e ndin g on the application ra t e and the e n viro nm e ntal conditions. This s hort durati o n of residual activity m ay be desirable for yo un g pl a nt production , s in ce th e growt h inhibiti o n may be not be de s irabl e afte r transplanting ( Runk le , 20 1 3)
. 

### REFE R EN CE S Runkle , E
. 2013
. Successfo l Use of the PGR Dam i no z ide
. Greenhouse Product News
. Online Publication. Avai l able at: http ://www . gpnmag.com/successful

- u sc-p gr-daminozide
. Access e d on April 3, 2015
. USE PA. 1993. Re g i strat io n E li gib ili ty De c i s io n . D am i nozide. Onl ine Publ ication. Available at: http ://www.cpa . gov/ oppOOOO l / chem search/reg actions/ reregi s tratio n/ red PC

035101 l-Sep-93.pdf. A ccess ed on A pril 3 , 20 15.
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