Location: Mosquito and Fly Research2016 Annual Report
1. Evaluate the effects of climate change on filth fly populations and their natural enemies. 1A. House fly management under high temperature conditions. 1B. Verify seasonality, resource preference and range of Stomoxys niger in East Africa. 2. Increase the efficiency of integrated pest management programs by the development and improvement of traps and behavior-altering surfaces and chemicals. 2A. Identify and develop stable fly optical or chemical attractants which will improve trap efficacy. 2B. Conceive of or develop applications for behavior-altering devices, surfaces and chemicals (e.g., attractants, repellents, and pesticides) for practical use on and around livestock and poultry. 3. Develop management techniques for fly larvae. 3A. Development of more effective larval detection and control techniques for filth flies. 3B. Autodissemination of Insect Growth Regulators (IGR’s) by house flies. 4. Improve biological control techniques for filth flies. 4A. Improved efficacy of Beauveria bassiana by formulating combination products with other agents. 4B. Location of host pupae by filth fly parasitoids. 4C. Improve the quality of commercially available fly parasitoids.
Objective 1 will investigate and identify methods for management of house flies under the higher temperatures expected to occur with global warming. It will also use trapping data to determine risk of introduction of exotic Stomoxys spp. in the U.S. Objective 2 will develop chemical or optical attractants that will enable traps for stable flies to become more efficient and capture greater numbers of flies. It will also adapt behavior-altering devices, such as pesticide-impregnated fabrics, for different uses, such as attract and kill devices. Objective 3 will evaluate new methods for determining the presence of sub-surface immature fly populations in field habitats. It will also further develop methods to allow house flies to spread selected IGRs throughout their habitats. Ojective 4 will improve the efficacy of a biological control agent by formulating it with other selected lethal agents. It will also investigate the methods (e.g., chemical cues) used by parasitic wasps to locate fly pupae in field habitats. Finally, we will gain new knowledge on the effects of long-term colonization on the performance of parasitic wasps being released into the field.
During the second year of this project, house flies and four species of parasitoids from Florida, Nebraska, Minnesota, and California were assessed for heat tolerance. Muscidifurax (M.) zaraptor was the most heat tolerant, followed by M. raptor, Spalangia (S.) endius, and S. cameroni. Flies and parasitoids collected from different states were mostly similar in their heat tolerance except that Minnesota flies were less heat tolerant than the other fly strains. Fifteen generations of selection under high temperatures resulted in house flies with significantly higher heat tolerance. Contact has been maintained with the cooperator for the stable fly project in Kenya. State Department travel restrictions to Kenya have been eased and visits may be allowed in the upcoming year. New materials that are optically attractive to stable flies have been identified and evaluated in the laboratory and the field. These allow for the capture of significantly more flies on traps. Behavior-altering devices for application to fly resting site have been identified. These devices either repel the flies or capture them on the surface. Dose-response studies indicated that pyriproxyfen had no effect on Spalangia endius or S. cameroni at any dose. Muscidifurax raptor and M. zaraptor were somewhat susceptible, with LC50’s of ca. 0.01% PPF. The LC50 for house flies was <0.0001%. A new design for a PPF autodissemination station was tested in the field using three attractants; 25% molasses was the most effective attractant, followed by Farnam fly attractant and Zumbafly. Strains of Beauveria bassiana and Serratia marcescens were screened for activity against house fly adults, and preliminary testing was done using a variety of carriers to identify carriers that provide good coverage on fly cuticle while maintaining viability of the pathogens. Capture of headspace volatiles produced by fly larvae developing in selected laboratory media or substrates is underway after the evaluation of selected capture methods. The current method will allow capture of chemical without changing the behavior or activity of the larvae within the substrate.
1. A sticky trap component is found to be inherently attractive to stable flies. The Knight Stick (KS) Fly Trap consists of a vertically oriented cylindrical resonating chamber covered by a thin, adhesive-coated KS foam wrap that captured 3 to 5 times more stable flies than devices currently in use. In competitive studies with other commercially available traps, ARS researchers at Gainesville, Florida, found the KS wrap alone was very attractive to stable flies. When wrapped around non-attractant items, e.g., propane tanks, barrels, the KS wrap performed similarly to KS wraps applied to the resonating chamber of the KS trap. This finding increases the versatility of the KS wrap because it is not limited to use on the KS trap. The KS trap is a very effective tool for stable fly management around cattle, and the KS wrap alone can be used in locations unsuitable for trap placement. The KS trap and KS wraps greatly impact animal welfare by significantly reducing fly feeding on animals A publication has been submitted.
2. Change in shape and size render fly attract and kill device easier to use in field conditions. Flat 1-m2 cloth targets have been found to be effective for stable fly management around cattle, but the flat configuration is not resistant to winds typically found in the Great Plains states where cattle are concentrated. ARS researchers at Gainesville, Florida, changed target configuration from flat to cylindrical and reduced size from 1 m high to 30 cm high without affecting efficacy. Smaller cylindrical configuration makes targets easier to handle and deploy in the field. Smaller size means targets can be placed closer to cattle where they are most effective. Smaller size also means effective stable fly management with less cost to cattle producers. Targets will increase animal welfare by assisting in fly management in difficult to treat areas.
3. Stable fly identified as a major urban pest in zoological parks. In the process of identifying and developing stable fly optical and chemical attractants, it was discovered that stable flies are a major pest species in zoological parks in many U.S. cities. Adults arrive from unknown sources and cause irritation to zoo animals by their painful bites. Because of pesticide sensitivities associated with zoological parks, ARS researchers at Gainesville, Florida, have worked with zoo personnel to develop stable fly integrated pest management (IPM) programs based on pesticide-free interventions, such as sticky traps and fans. A pesticide- treated fabric, considered a focused use of pesticides, has been used at selected locations. By modifying these programs to best fit local conditions, zoo personnel have improved animal health and welfare by reducing stable fly populations by 50% or more.
4. House flies and stable flies are important pests associated with animals and humans and transmit a wide array of disease organisms. Biological control is an important element in successful fly management, and naturally occurring fungi can kill these flies. But little is known about how fungi, primarily Beauveria bassiana and Metarhizium anisopliae, affect immature fly development and egg laying by house and stable flies. In this study, conducted by scientists at USDA’s Center for Medical, Agricultural and Veterinary Entomology in Gainesville, Florida and the University of Florida, five commercially available products containing B. bassiana or M. anisopliae were tested for sublethal effects. House flies and stable flies laid very few eggs on surfaces treated with the M. anisopliae product. Stable flies also did not lay many eggs on the organic B. bassiana product. Immature house flies had greater mortality after hatching on surfaces treated with M. anisopliae. These results demonstrate that commercial products, primarily the one with M. anisopliae, can be used to deter egg laying by flies as well as killing the fly larvae that hatch from the eggs.
5. Insect production over many years can lead to an inferior product, yet commercial insectaries produce and sell fly parasitoids to farmers and ranchers for fly control. How good is the quality of the parasitoids available for fly control? In this study, scientists at USDA’s Center for Medical, Agricultural and Veterinary Entomology in Gainesville, Florida and the University of Florida examined the effects of long colonization on a species of wasp that is commonly sold for fly control, Spalangia cameroni. Long-colonized wasps were less effective than newly colonized parasitoids at finding and killing fly pupae, especially when they had to search for pupae under simulated natural conditions. The results indicate that researchers and commercial wasp producers should start with fresh colonies every few years to ensure production of high quality insects for use in research and fly control.
6. High temperatures present new challenges for house fly management. Most of the available information on the efficacy of biocontrol agents for house fly control has been obtained from temperate climates such as found in North Carolina, California, and New York. Climate change predictions indicate that future fly management may be conducted under temperature conditions that historically would have been considered extreme. How do fly parasitoids (biocontrol agents) perform under very hot conditions? Using experimental conditions simulating July conditions in cool, moderate, and very hot locations in the U.S., ARS researchers at the Center for Medical, Agricultural and Veterinary Entomology in Gainesville, Florida found that hot conditions greatly reduced the effectiveness of all species of parasitoids and that flies are intrinsically much more heat tolerant than their natural enemies. Surprisingly, flies from moderate-temperature locations such as Minnesota and Nebraska were similar in their heat tolerance to flies from Florida and the Mojave Desert. Rising temperatures would likely result in substantially higher fly populations unless new management strategies are devised.
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Machtinger, E.T., Geden, C.J., Lovullo, E.D., Shirk, P.D. 2015. Impacts of extended laboratory rearing on female fitness in Florida colonies of the parasitoid spalangia cameroni (Hymenoptera: Pteromalidae) with an analysis of wolbachia strains. Annals of the Entomological Society of America. 109(2):176-182.