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United States Department of Agriculture

Agricultural Research Service

2009 Annual Report

1a.Objectives (from AD-416)
Develop liquid culture methods for producing microbial biocontrol agents by optimizing the nutritional and environmental conditions during growth for the production of an appropriate microbial propagule with optimal biocontrol efficacy and storage stability. Develop novel formulation technologies for microbial biocontrol agents and natural products through the selection and application of innovative processes and ingredients that lead to improved efficacy, storage stability, field stability and product delivery.

1b.Approach (from AD-416)
Our research strategy will focus on developing liquid culture methods for producing microbial biocontrol agents by optimizing the nutritional and environmental conditions during growth for the production of an appropriate microbial propagule with optimal biocontrol efficacy and storage stability. Formulation-based solutions to critical problems related to biocontrol agent stability, efficacy, and application will be addressed by evaluating the impact of formulation ingredients and processes on the physical characteristics, biological activity, storage stability, and field efficacy of selected biocontrol agents.

3.Progress Report
Microbial-based pest control products (i.e., biopesticides) have promise as a “green” strategy for controlling insects and weeds. Commercialization requires the development of cost-effective production, stabilization, and formulation technologies. During FY 2009, we conducted production and formulation studies with a variety of biocontrol microorganisms. We refined production and formulation processes for Mycoleptodiscus terrestris (MT), a fungal bioherbicide being developed for use against the aquatic weed hydrilla. In collaboration with a commercial partner and the U.S. Army Corps of Engineers, summer field trials with MT suppressed hydrilla growth in a test pond in Florida. Fall field trials showed enhanced hydrilla biomass reduction 3 months post application when MT was used with low dose rates of chemical herbicides. These studies identified promising application approaches and are part of an effort to commercially develop MT as a non-chemical control tool for hydrilla. In addition, optimization of a novel production process for the bioinsecticidal fungus Metarhizium anisopliae is continuing and promises to improve the effectiveness of this agent in controlling soil-dwelling insects.

Formulations of the insect-killing fungus Isaria fumosorosea (Pfr), mass-produced using patented ARS technology, were evaluated for controlling a number of serious insect pests including the Formosan subterranean termite, pecan aphid, and Asian citrus psyllid (ACP). In collaboration with ARS scientists in New Orleans, biocompatible foam formulations of Pfr showed promise for controlling Formosan subterranean termite infestations in living trees. Studies with ARS scientists in Georgia have shown that Pfr blastospores infect and kill the pecan aphid suggesting its potential use in controlling this serious pest. Pfr is also being evaluated as a biopesticide for controlling ACP, an invasive insect pest that poses a serious threat to the citrus industry. ACP studies are being conducted in collaboration with ARS scientists in Florida and Texas and University of Florida scientists. Formulation studies have shown viable, infective spores of Pfr can be applied as thin films on the surface of ACP bait stations. The development of Pfr for control of these important insect pest targets will improve the commercial potential of this promising bioinsecticide.

Microbial-based insecticides are rapidly inactivated by sunlight. We have developed a lignin-based formulation to protect viral and bacterial insect biopesticides from the harmful effects of solar radiation. Soyscreen (a natural sunscreen) protected the fungal biopesticide (Beauveria. bassiana) from degradation when exposed to sunlight. However, no significant benefit was seen in field trials. Formulations that protect against UV damage extend insecticidal activity and improves the commercial potential of these microbial insecticides. These FY 2009 studies have advanced our basic and applied knowledge on the production and formulation of microbial biopesticides, enhancing their commercial potential with the goal of providing the American farmer effective, non-chemical pest control tools.

1. SOLAR PROTECTION FOR MICROBIAL INSECTICIDES. Microbial-based insecticides have tremendous promise as a "green" pest control strategy, but microbes are rapidly inactivated by sunlight. We have developed techniques to protect viral and bacterial insect control agents from the harmful effects of solar radiation. Lignin (a by-product of the paper industry) is an effective ultraviolet screen when formulated with microbes providing a protective film when they are sprayed onto crops. Protection against ultraviolet damage improves the commercial potential of microbial insecticides by extending their insecticidal activity.

2. CONTROL OF SUGAR BEET ROOT MAGGOTS WITH FUNGUS. Soil-dwelling insects pose a serious problem in agricultural and urban environments. The fungus Metarhizium anisopliae (Ma) infects and kills many insect pests including those found in the soil. We have developed a method for producing a very stable form of Ma, a microsclerotium, using liquid fermentation. Production scale-up experiments confirmed that high concentrations of stable microsclerotia were rapidly produced using pilot-scale fermentors. When dried microsclerotia of Ma were soil incorporated with sugar beet seeds, they germinated to produce infective conidia that infected and killed the sugar beet root maggot. The development of Ma as a non-chemical control for the sugar beet root maggot will provide farmers with another tool to control this troublesome pest.

3. HYDRILLA CONTROL IN FLORIDA WITH FUNGUS-HERBICIDE COMBINATION. The fungus Mycoleptodiscus terrestris (MT) is being developed as a bioherbicide for control of the invasive aquatic weed hydrilla which is showing resistance to the most commonly used herbicide, fluoridone. Field trials demonstrated enhanced hydrilla biomass reduction three months post application when MT was used with low dose rates of the chemical herbicides endothall or penoxsulam. These studies demonstrated that MT has potential to control hydrilla growth when applied at water temperatures conducive to MT growth with enhanced activity against hydrilla when applied with low doses of chemical herbicides. The development of MT as a commercial bioherbicide will provide water management specialists with an important non-chemical control tool for this serious aquatic weed.

6.Technology Transfer

Number of Active CRADAs1
Number of Invention Disclosures Submitted1

Review Publications
Koppenhofer, A.M., Behle, R.W., Dunlap, C.A., Fisher, J., Laird, C., Vittum, P.J. 2008. Pellet Formulations of Sex Pheromone Components for Mating Disruption of Oriental Beetle (Coleoptera: Scarabaeidae) in Turfgrass. Environmental Entomology. 37(5):1126-1135.

Arthurs, S., Lacey, L.A., Behle, R.W. 2008. Evaluation of Lignins and Particle Films as Solar Protectants for the Granulovirus of the Codling Moth, Cydia pomonella. Biocontrol Science and Technology. 18:829-839.

Shapiro Ilan, D.I., Cottrell, T.E., Gardner, W.A., Leland, J., Behle, R.W. 2009. Mortality and mycosis of adult Curculio caryae (Coleoptera: Curculionidae) following application of Metarhizium anisopliae: laboratory and field trials. Journal of Entomological Science. 44:24-36.

Jaronski, S., Jackson, M.A. 2008. Efficacy of Metarhizium anisopliae microsclerotial granules. Biocontrol Science and Technology. 18(8):849-863.

Behle, R.W., Cosse, A.A., Dunlap, C.A., Fisher, J., Koppenhofer, A. 2008. Developing Wax-Based Granule Formulations for Mating Disruption of Oriental Beetles (Coleoptera: Scarabaeidae) in Turfgrass. Journal of Economic Entomology. 101:1856-1863.

Last Modified: 2/27/2015
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