Traps, attractants, targets and insecticides for house flies

1. Traps, attractants, targets and insecticides for house flies Christopher J. Geden USDA, ARS, CMAVE

2. Traps, attractants, targets and insecticides for house flies 1)Trap height • Fresh vs. fermenting sugar baits • Insecticide-treated targets • Status of imidacloprid resistance • Pyriproxyfen and endosulfan for fly control

3. Topic 1: Trap height In a previous DWFP project, the Terminator was identified as the most effective jar trap for house flies. Outcomes: publication and issuance of a NSN for the Terminator. Geden, C. J., D. E. Szumlas and T.W. Walker. 2009. Evaluation of commercial and field-expedient baited traps for house flies, Musca domestica L. (Diptera: Muscidae). J. Vector Ecol. 34: 99-103

4. House flies tend to fly low to the ground. At what height should the traps be placed?

5. The traps work best when placed on the ground or suspended just above Data from research of graduate student Melissa Doyle

6. Topic 2: fresh vs. fermenting molasses The attractant used in the Terminator is a combination of trimethylamine, indole/skatole, and z-9-tricosene. Effective, but stinky!

7. Does fermentation increase attractiveness of molasses? • Background • Flies have been observed to be attracted to molasses since antiquity. • In previous years, blackstrap molasses was found to be as attractive as the bait used in Terminator traps. • Flies also visit a variety of fermenting food sources in the field. • Hypothesis: That flies use volatile products from fermentation such as ethanol and CO2 as stimuli indicating the presence of sugar sources. • 2 Methods: • Molasses with and without live yeast placed in field and monitored for 4 days. • Molasses allowed to ferment indoors for 1 or 2 days then placed in the field and compared with fresh molasses.

8. Effect of fermentation of molasses on attractiveness to house flies Flies were more attracted to unfermented than to fermented molasses, at least in jar traps. Do the high CO2 levels associated with primary fermentation deter flies from entering the traps? Data from research of graduate student Melissa Doyle

9. Topic 3: Insecticide-treated targets for fly control/interception In an ongoing project, visually attractive targets have been tested for their ability to intercept and kill dispersing flies. The most attractive configuration consists of adjoining bands of alsynite fiberglass and blue fabric with peak reflectance at 460 nm. Joe Declaro and Phil Koehler are also developing a trap that takes advantage of this color preference.

10. In 2008, a perimeter of targets provided significant protection of a large structure (calf barn) from fly invasion from surrounding breeding sites. Target performance improved substantially when an olfactory lure (Farnam fly attractant) was added.

11. Treated targets, 2009: Low apparancy targets using olfactory lures • Questions: • Can an olfactory fly attractant be used in a low-apparency attract-and-kill device? • Are kill rates in such a device higher than in a conventional jar trap baited with the same attractant? • Can the attractant be conserved by a slower release method?

12. Attractant delivery using conventional Captivator jar traps

13. Buckets (containing nothing or attractant in Captivator traps or slow-release devices) were wrapped with camo and tied at top and bottom to prevent fly entry. • Netting was treated with imidacloprid/sugar solution, allowed to dry. • Pans were placed below targets to collect killed flies.

14. Geden – USDA, ARS, FL • Results: • Treated targets with attractant collected 2x more flies than jar traps or targets without attractant. • Targets were easy to service, no handling of smelly liquids • Treated camouflage netting without attractant was surprisingly effective. The complex pattern may present a visually attractive target to the flies.

15. Topic 4: Imidacloprid resistance Imidacloprid for fly control first appeared in ca. 2002 as a scatter bait. The bait’s success gave rise to other application methods that may increase the likelihood of resistance development, despite the fact that neonicotinoids represent “new chemistry” with low risk of cross-resistance from other insecticide classes.

16. A recent survey found imidacloprid resistance in all populations tested. In one case, resistance was high enough that product failure is imminent. There is a critical need for new active ingredients for fly control. Data from Kaufman et al. 2009, Insecticide resistance in house flies collected from Florida dairies. Pest Management Sci. (in press)

17. Pyriproxyfen • Discovered in the early 1980’s • JH analogue • Low mammalian toxicity (acute oral LD50>5000) • Breaks down rapidly in soil and water • Discovered in early 1980’s • Early work indicated some potential for tsetse, stable flies, house flies.

18. Pyriproxyfen (continued) • Trade names: Knack, Nylar, Sumilarv, Nyguard • Main targets: Homoptera, fleas, mosquitoes • For mosquitoes and flies in the US, the only EPA-registered product is Nyguard, with only adults listed. Face flies are on the label but not house flies. The label does not include application as a larvicide. • Outside the US, Sumilarv is sold in granular and liquid formulations as a larvicide for mosquitoes and flies.

19. In a recent paper, Devine et al. observed substantial control of Aedes aegypti by treating mosquito resting sites with pyriproxyfen and allowing the mosquitoes to transfer the ppx to larval habitats. Could a parallel approach be effective against house flies?

20. When flies were held continuously in cages with treated filter paper, fecundity was reduced, but only at 125X the label rate.

21. However, flies given ppx in a dry sugar bait had reduced fecundity at lower doses. Still no effect on emergence success of flies from pupae of treated groups.

22. Results with wild flies were essentially the same as those with insecticide-susceptible colony flies, except 2 flies emerged from pupae at the lowest dose.

23. Summary, preliminary pyriproxyfen tests: • ___________________________________________ • PPX shows promise for fly control • It is a potent IGR against house fly immatures • Little to no evidence of tolerance in wild flies • Although there is little effect on fly adults during short exposures, incorporation into baits reduces fecundity, as does frequent contact with a treated surface over longer time frames.

24. Endosulfan • Developed in the 1950’s • Organochlorine • High mammalian toxicity (acute oral LD50 35 mg/kg) • GABA-gated chloride channel antagonist • ATPase inhibitor • Broad spectrum • Trade names: Benzoepin, Endocel, Parrysulfan, Phaser, Thiodan, Thionex • Most uses have been banned, but….

25. Avenger ear tags containing 30% endosulfan were introduced in 2007 for fly control on cattle (but not soldiers!). Marketed as “new chemistry”, the tags are highly effective against insecticide-resistant horn fly populations.

26. Adult house flies were highly susceptible to endosulfan (Thionex) when exposed to filter paper treated at the label rate for control of Homoptera on cotton. There was no recovery of flies between 4 and 24 hr after exposure.

27. Even at a high dose, a substantial exposure time to endosulfan was required

29. Summary, preliminary endosulfan tests • ______________________________________ • Endosulfan is highly toxic to insecticide-susceptible and wild house flies. • Some evidence for higher recovery rates in wild flies • Use as a residual treatment would rapidly lead to resurgence of resistance. • Are there targeted applications that would allow use of this old-school insecticide in ways that would be safe and not lead to rapid resistance development?