Traps, attractants, targets and insecticides for house flies

Christopher J. GedenUSDA, ARS, CMAVE

Traps, attractants, targets and insecticides for house flies

1)Trap height1)Fresh vs. fermenting sugar baits2)Insecticide-treated targets3)Status of imidacloprid resistance4)Pyriproxyfen and endosulfan for fly

control

____________________________________________ Trap Mean catch % catch ____________________________________________ Terminator 12,323.0a 100.0 Final Flight 2,166.5b 17.6 Victor Fly Magnet 1,287.0c 10.4 Monster Flies-Be-gone 883.0c 7.2 ISCA 276.8d 2.2 Advantage 202.5d 1.6 Fermone Big Boy 132.8d 1.1 Squeeze & Snap 79.3d 0.6 Oak Stump (blue trap) 15.5e 0.1

____________________________________________

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

Topic 1: Trap height

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

Effect of trap height on house fly collections in Terminator traps

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Low (0.25 m) Med (0.9 m) High (1.7 m)

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Data from research of graduate student Melissa Doyle

The traps work best when placed on the ground or suspended just above

The attractant used in the Terminator is a combination of trimethylamine, indole/skatole, and z-9-tricosene. Effective, but stinky!

Topic 2: fresh vs. fermenting molasses

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.

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Unfermented 24 hr ferment 48 hr ferment

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Effect of fermentation of molasses on attractiveness to house flies

Data from research of graduate student Melissa Doyle

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?

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.

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.

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?

Treated targets, 2009: Low apparancy targets using olfactory lures

Attractant delivery using conventional Captivator jar traps

• 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.

Fly collections from insecticide-treated, camouflage-covered targets and from uncovered Captivator traps. ____________________________________________________ Device Mean flies/day ____________________________________________________ Camo-covered chick waterer w/ attractant 2219.6 (466.9)a Camo-covered Captivator w/attractant 2189.7 (555.0)a Camo-covered bucket, no attractant 1298.4 (286.7)b Captivator control (no camo cover) 1137.5 (238.0)b ____________________________________________________ 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.

Geden – USDA, ARS, FL

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.

Topic 4: Imidacloprid resistance

Sensitivity to imidacloprid in colony and field-collected house flies

Strain n LC90 (µgg-2) (95% CI) RR90b Slope (SE)

Susc. colony 1,920 65 (52-89) - 2.3 (0.2)

UF 05-06c 1,760 143 (122-173) 2.2* 2.2 (0.1)

UF 07 c 2,160 446 (369-555) 6.8* 1.7 (0.1)

Gilchrist 1,920 346 (273-462) 5.3* 1.7 (0.1)

Lafayette 2,160 1,550 (1,276-1,941) 23.7* 1.6 (0.1)

Okeechobee 1,920 202 (159-274) 3.1* 1.9 (0.1)

Data from Kaufman et al. 2009, Insecticide resistance in house flies collected from Florida dairies. Pest Management Sci. (in press)

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.

• 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.

Pyriproxyfen

• 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.

Pyriproxyfen (continued)

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?

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

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.

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.

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.

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….

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.

Mortality of insecticide-susceptible house flies after a 1hr exposure to Endosufan

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Control 0.009 0.028 0.084 0.253 0.758

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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.

Mortality of house flies after varying periods of exposure to 0.76% Endosulfan

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Control 1 min 5 min 10 min 20 min 40 min

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

Mortality 4 hr after exposure to endosulfan

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Control 0.009 0.028 0.084 0.253 0.758

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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?