REDUCING INSECTICIDE RUNOFF FROM HOUSES TREATED FOR ANT INFESTATIONS Dr. Les Greenberg University of California, Riverside
Problem Pyrethroids and fipronil have been found in urban waterways in CA and other states State and national regulatory agencies are concerned about runoff of these insecticides
Why runoff matters Water contaminated with insecticides can go from the house to the street (mainly via the driveway) and then to sewers that feed into urban waterways These aquatic waterways contain small crustaceans that are highly susceptible to insecticides
Fresh water crustacea Important components of fresh water food chains Consume algae and other small organisms and are then fed on by fish, insect larvae and other small organisms They are indicator species for toxins in the environment
Daphnia Water flea (Daphnia, Ceriodaphnia) Mysid shrimp
Water runoff from lawns
Especially driveways Irrigation runoff from a typical house
Measuring insecticide runoff
Dam placement at curb Sand bags on styrofoam Styrofoam and sand bags put inside disposable plastic bags
Sample collection
Driveway sample collection
Definitions LC 50 = lethal concentration that kills 50% of the test organism For aquatic organisms, frequently described in terms of parts per billion (ppb) or parts per trillion (ppt) One ppb = 1,000 ppt
Water runoff One part per trillion (ppt) is equivalent to one drop of water diluted into 20 Olympic-size swimming pools (50,000 m 3 ). (Source: Wikipedia)
LC 50 s of fipronil and bifenthrin against aquatic test organisms Test organism fipronil (ppt) bifenthrin (ppt) Rainbow trout 248,000 150 Bluegill 85,000 350 Sheepshead minnow 130,000 17,500 Grass shrimp 320 ---- Aedes albopictus 810 5,200 Mysid shrimp 140 4 Ceriodaphnia 10,000-32,000 78 Daphnia magna ---- 320
FIRST RUNOFF TRIALS, 2007: BEFORE LABEL CHANGES FOR FIPRONIL AND PYRETHROIDS
Concentration in ppb 1.00 0.10 Concentration in µg/l10.00 B gran B spray F perim F spot Ceriodaphnia LC 50 for fipronil (10 ppb) Ceriodaphnia LC 50 for bifenthrin (0.078 ppb) 0.01 0 1 2 3 4 5 6 7 8 9 Week
2008
10.00 Fipronil concentration in µg/l ppb PPB 1.00 0.10 pin perimeter fan spot fan spot + SFZ Pin perimeter 0.01 0 5 10 15 Day Ceriodaphnia LC 50 For fipronil (10 ppb) Mysid shrimp LC 50 (0.14 ppb)
Fipronil runoff 2010 Variety of applications
Fipronil treatments Perimeter spray Perimeter spray minus driveway Wet foam perimeter Dry foam perimeter Perimeter spray with narrow band at garage door
1-gal 0.06% fan spray limited to house foundation, 1 ft up and 1 ft out
1-gal pin stream application around entire house foundation and narrow band at garage
Foam applicator from NPD Products, Canada
Preparing the wet foam
Wet foam application of 0.06% fipronil 1 ft up and 1 ft out from foundation
Dry foam aerosol application of 0.65% fipronil
Fipronil runoff Ceriodaphnia LC 50 Concentration in ppt 10,000 1,000 100 10 1 Mysid shrimp LC 50 1 7 21 56 Days post-treatment 40 gal wash of Building and driveway Treatment C&C DryFoam NoDoor Standard WetFoam
2011 Bifenthrin spray alternatives
Fipronil spray and bifenthrin granules 0.5 gal pin stream fipronil, avoiding garage door and driveway completely Supplementing fipronil with two kinds of bifenthrin granules Talstar PL, sand matrix Talstar Verge, clay particles
Percent reduction in ant numbers Percent reduction 80 70 60 50 40 30 20 10 0 1 2 4 8 Weeks post-treatment Treatment Term Term+PL Term+Verge
Comparing narrow band pin stream vs. crack and crevice in expansion joint at garage door for fipronil runoff 2012
Pin stream at garage
Crack and crevice at garage
Concentration in ppt 10,000 1,000 100 10 Fipronil runoff Company 1 Company 2 Ceriodaphnia LC 50 (10,000 ppt) Mysid shrimp LC 50 (140 ppt) 1 0 10 20 30 40 50 60 70 80 90 100 Days post-treatment
Fipronil and bifenthrin runoff 2013
Company protocol to reduce runoff Limited use of bifenthrin in front of house, nothing closer than 2 ft from driveway. Mostly used natural pyrethrins in front of house. No fipronil on driveway; at least 1 ft away
Fipronil runoff Ceriodaphnia LC 50 (10,000 ppt) 10,000 1,000 Mysid shrimp LC 50 (140 ppt) PPT 100 10 1 04/01 05/01 06/01 07/01 08/01 09/01 10/01 2013 Component desulfinyl fipronyl sulfide sulfone
Bifenthrin spray runoff 10,000 1,000 Ceriodaphnia LC 50 (78 ppt) Mysid shrimp LC 50 (4 ppt) PPT 100 10 Switched to avermectin bait 1 04/01 05/01 06/01 07/01 08/01 09/01 10/01 2013
Particulates vs. liquid in runoff Percent runoff as particulates 100 90 80 70 60 50 40 30 20 10 c a b ab b 0 bifenthrin fipronil desulfinyl Insecticide sulfide sulfone
Testing driveway alternatives Houses treated only with pin stream fipronil (0.5 gal) around the house foundation, and not closer than 1 ft from driveway Driveway substitutions Botanical sprays Indoxacarb sprays Thiamethoxam gel in buried bait stations
Alternatives to fipronil on driveway 120 100 % reduction 80 60 40 20 0 Wk1 Wk2 Wk4 Wk8 Weeks post-treatment Treatment fipronil fipronil + indoxacarb fipronil + botanicals fipronil + thiamethoxam gel
2013 Runoff from fipronil, no driveway Effect of paint on driveway 1,000 Mysid shrimp LC 50 1 house Painted driveway Fipronil in ppt 100 4 houses 10 No paint Paint Pretreat Day1
2014
Runoff from different bifenthrin applications Narrow band, 2x2 in Wide band, 2 ft up, 3 ft out Wide band, 2 ft up, 3 ft out, plus crack and crevice along driveway edges Spot treatment at 2 ft from driveway Spot treatment at 6 ft from driveway 5 houses per treatment No treatment at garage door
1,000 Bifenthrin ppt 100 10 1 Days post-treatment TREAT$ 2x2in 2x3ft 2x3ft&DW spot6ftaway
Band width runoff comparisons Bifenthrin ppt 1,000 100 10 1 28 Days post-treatment Spot treatment at 2 ft from driveway added TREAT$ 2x2in 2x3ft&CC 2x3ft&DW
Bifenthrin efficacy % reduction in ant numbers 100 90 80 70 60 50 40 30 20 10 0 Bifenthrin treatments 2014 wk1 wk2 wk4 Weeks post treatment Treatments 2x2 in 2x3 ft 2x3 ft C&C
How to reduce bifenthrin runoff Avoid front of house or impervious surfaces leading to front of house Substitute granular pyrethroid for front of house, keeping away from driveway If you must spray at garage door, use a crack and crevice application directly into the expansion joint Use narrow band around perimeter For front of house and driveway substitute botanicals, other non-pyrethroids, baits
Runoff from different fipronil band widths Narrow band pin stream, 2x2 in Wide band, 6x6 in No treatment at garage door 5 houses per treatment
Day 1 250 200 Mysid shrimp LC 50 Fipronil ppt 150 100 50 0 6x6in pin pin rain Treatment
How to reduce fipronil runoff Highlights: Reduce fipronil use to 0.5 gal using a narrow band If spraying at garage door/driveway, do a crack and crevice into the expansion joint Even better, avoid the driveway/garage door interface completely Avoid use in rainy season
Collaborators Mike Rust, University of California Dong-Hwan Choe, University of California Kathleen Campbell, University of California Sara Jean Wright, University of California Pat Copps, Orkin Pest Control Keith Willingham, Western Exterminator Company Corky Mizer, Corky s Pest Control