**United States Department of Agriculture Animal and Plant Health Inspection Service**  **Plant Protection and Quarantine** 

## Administrative action to **change D301**  **- 81**  **- 10(3) and D301.81**  **-**

**10(8) i**  **n the Treatment Manual**  **Treatment Evaluation Document**  (TED )

**D ate**  : June 20, 2012 **Treatments, Pests, and**  **Commodities New Treatment/**  **Revision/Deletion Treatment** 

**Type Target Pests**  **Commodity Applicable** New treatment Bifenthrin Solenopsis invicta; Solenopsis richteri and hy brid (Imported Fire Ant) Balled - and - burlapp ed

plants/nursery

stock; immersion/dip application

New treatment Bifenthrin Solenopsis invicta; Solenopsis richteri and hy brid (Imported Fire Ant) Commercial Grass sod

Clarification of application method Drench

method on balled - and burlapped plants Solen opsis

invicta; Solenopsis richteri and hy brid (Imported Fire Ant) Balled - and - burlapped

plants/nursery

stock; drench application2

**Objective :**  To provide supporting in formation and justification for additional treatments being proposed for the Imported Fire Ant (IFA) quarantine in the Treatment Manual. The change is to help continue domestic trade of nursery stock from areas of the U.S. infested with Solenopsis invicta, Solenopsis richteri and the hy brid (Imported Fire Ant) . **Overview:** In order to limit th e artificial spread of the Imported Fire Ant, domestic movement of all nursery

stock (containerized or balled - and - burlapped) and grass sod from IFA - infested areas of the U.S. to uninfested areas is regulated under 7 CFR 301.81 - 2. Current approved treatments for balled - and - burlapped (B&B) nursery stock is limited to the use of one insecticide, chlorp yrifos, and availability of that insecticide is very limited, with only

a handful of EPA approved labels with pest, commodity and required quarantine level effe ctive rates of application. Treatment of grass sod is similarly limited by available EPA approved insecticide labels. While 2 insecticides are APHI S approved, no chlorp yrifos labels for grass sod and IFA at quarantine level rates of application are avail able (use pattern has been cancelled/removed from labels due to EPA chlorpy rifos concerns). Grass sod can be treated with granular fipronil, but many sod growers are not comfortable with granular applications, nor have granular application equipment. The refore, CPHST is continually pursuing additional quarantine level treatment options and better application techniques for growers to comply with the Imported Fire Ant quarantine. **Evaluation :**  Bifenthrin immersion treatment for b alled - and - b urlapped n urse ry s tock : CPHST, along with Tennessee State University , have evaluated the use of bifenthrin as an immersion treatment for balled - and - burlapped nursery stock for 2 - 4 years. The results found that a dip rate of 0.115 lb ai/100 gal water provided 6 months of residual activity against IFA . Thus, CPHST recommended the addition of this treatment option to the Treatment Manual. Bifenthrin treatment for grass sod : CPHST, along with Tennessee State University , have evaluated the use of bifenthrin as a grass so d treatment for over 2 - 3 years. The results found bifenthrin liquid applied in two applications, one week apart, as a broadcast application at a rate of 0.2 lb ai/acre provided 16 weeks of residual activity against IFA after a four week exposure period. Thus, CPHST recommended the addition of this treatment option to the Treatment Manual. Clarification of application method for drench treatment of balled - and - burlapped nursery stock: During drenching, B&B normall y rests on one side of the root ball throu ghout the three - day

drench process (drench twice a day for 3 consecutive days) . This drench method possibly restricts treatment coverage on the resting side, while giving the surface of direct application a higher concentration of chemical and deeper pene tration. Trials conducted by CPHST and Tennessee State University in the mid 2000s, strongl y suggested that rotating root balls during treatment, regardless of application frequency , improved the consistency of bioassay

results and could potentially cut the number of days spent applying drenches from three down to one. Numerous trials3

have been conduct since 2005 to examine whether changes in plant handling during application improve d penetration and coverage and whether we could possibly reduc e in the number of day s required to complete a drench. Itis clear that rotating root balls during treatment application leads to a more uniform coverage of the spray treatment and more consistently

effective bioassay

results . Thus, CPHST is recommending adding language to the Treatment Manual to strongl y recommend that growers rotate the B&B root balls between daily

applications for the current chlorpy rifos treatment. R eports available online at the APHI S - PPQ - CPHST Gulfport Lab annual reports webpage: http://www.a

phis.usda.gov/plant_health/plant_pest_info/fireants/gulfport.shtml **Addition to Treatment**  **D301.81 -**  **10(3): Nursery Stock Balled or in Containers Method**  **A –**  **Immersion:** A fter Certification Period and Important Notice for Emulsifiable Chlorpy rifos Treatment of Balled or Containerized Plants : Pesticide: Bifenthrin (Liquid

– label must have use pattern) Dosage: Table 5 - 8 - XX Bifenthrin L iquid Dosage for Balled or Containerized Plants Bifenthrin Dosage Liquid with use pattern on label 0.115 lb ai/100 gal. wat er Exposure Period: Plants certifiable immediatel y upon completion of treatment. Certification Period: 180 day s Important: The professional user assumes responsibility for determining if bifenthrin is safe to treat plants under commercial growing co nditions.4

**Addition to Treatment D301.81 -**  **10(8): Grass –**  **Sod** Add to Table 5 - 8 - 9 and modify title Table 5 - 8 - 9. Dosages for Grass Sod Material Amount and dosage of

material Certification Period Exposure

Period Chlorpy rifos 8.0 lb ai/acre 6 weeks (afte r exposure period) 48 hours Fipronil - granular 0.0125 lb ai/acre applied in 2

applications 1 week apart for total of 0.025 lb ai/acre 20 weeks (after exposure period) 30 day s Bifenthrin - liquid 0.2 lb ai/acre applied in 2

applications 1 week apart for total of 0.4 lb ai/acre 16 weeks (after exposure period) 4 weeks (28

day s) **Additional language to clarify application technique for Treatment D301.81 -**  **10(3) Nursery Stock**  **– Balled or in Containers Method B**  **– Drench Balled**  **- and**  **- Burlapped**  **(B&B) Plants: Step 2 A**

**pply the solution:** Apply the chlorpy

rifos solution as a substitute for plain water to the plants during the routine watering activities. Do not remove burlap wrap from plants prior to treatment. Treat plants singly

or in groups with the chlorpy rifos solution to the point or runoff on a twice dail y schedule for three consecutive days. Rotate the root ball between applications to insure all sides of the root ball are sufficiently treated. **Decision :**  Amend the Treatment Manual under D301.81 - 10(3) and D301. 81 - 10(8) to add a new immersion treatment using bifenthrin for B&B nursery stock and a new broadcast treatment using bifenthrin for grass sod. Amend the language under D301.81 - 10(3) for the drench application technique for B&B plants to include rotating t he root ball between insecticide applications. **Originator :**  Charles L Brown , PPQ - EDP - IFA National Program Manager

Anne - Marie Callcott , PPQ - CPHST, Entomologist