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United States Department of Agriculture

Agricultural Research Service

2010 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
The fungus Isaria fumosorosea is a biological control agent for whiteflies, aphids, termites, and psyllids. We developed technology for the production and stabilization of infective spores of I. fumosorosea using a deep-tank fermentation process and an air-drying process that produced spore powders with a 2-year shelf-life. A biocompatible foam formulation was developed that effectively delivered spores to Formosan termite infestations in living trees and dry spore formulations were developed for use in termite bait stations. Spore surface properties were chemically characterized so that a rational approach to formulation would be possible. The fungus Mycoleptodiscus terrestris is being developed as a biological control agent for the aquatic weed hydrilla. We developed a fermentation process that produced high concentrations of microsclerotia, a stable form of the fungus. Harvesting and drying processes were developed for microsclerotia that resulted in an effective bioherbicide with a 12-month shelf-life. Field trials showed hydrilla suppression after application of microsclerotia with enhanced hydrilla control when used in combination with low-dose chemical herbicides or adhesive-based formulations. The development of M. terrestris as a bioherbicide will provide aquatic managers a safe, non-chemical control tool. A fermentation process was developed for the production of microsclerotia of the bioinsecticidal fungus Metarhizium anisopliae. Media, fermentation parameters, and drying processes were identified that reduced the fermentation time, increased microsclerotia yields, and enhanced product stability. Soil incorporation of dried microsclerotial granules provided excellent control of the sugar beet root maggot. This discovery will broaden the usefulness of M. anisopliae in controlling soil-dwelling insects. Various formulation and drying processes were developed for fungi, viruses, and natural oils being developed as insect control agents. Processing procedures, temperature limits, and essential ingredients were identified as critical for maintaining spore and virus viability during the spray-drying process. Formulation technology was developed for nootkatone, an oil used for tick control, that reduced oil loss under field conditions. A lignin-based formulation was developed that extended the effectiveness of Bacillus thuriengiensis and baculoviruses, improving their potential for effective pest control. Baits were developed for attracting a leaf beetle that feeds on saltcedar, an invasive weedy tree in the Western U.S. These baits will be useful to land managers for monitoring populations. Several new wax formulations enhanced the performance of insect pheromones, attractants, and repellents in field testing. Wax pellets are a promising delivery system for pheromones and other chemical attractants or repellents and provided a non-toxic pest control solution for use in agricultural and urban environments.

1. Fermentation process developed for insect biocontrol fungus. Soil-dwelling insects pose a serious problem in agricultural and urban environments. The fungus Metarhizium anisopliae (MA) infects and kills many serious insect pests including those found in the soil. The use of MA for control of soil-dwelling insects has been problematic due to difficulties in delivering a viable, infective form of the fungus. Crop Bioprotection Research Unit scientists at the National Center for Agricultural Utilization Research, Peoria, IL, have developed a method for producing a very stable form of MA, a microsclerotium, using liquid fermentation. Production scale-up experiments showed that high concentrations of stable microsclerotia were rapidly produced using pilot-scale fermentors. When mixed in moist soil, dried microsclerotia of MA were rehydrated and produced spores that infected and killed sugar beet root maggots. Microsclerotia of MA show excellent potential for commercial development as a non-chemical control for soil-dwelling insects. The development of microsclerotia-based insect control products will provide farmers, land managers, and homeowners with another safe, non-chemical tool for managing insect problems.

2. Hydrilla control with fungal biological control agent. Hydrilla is showing resistance to the most commonly used chemical herbicide, fluoridone, at recommended use-rates. The fungus Mycoleptodiscus terrestris (MT), a natural enemy of hydrilla, is being developed as a bioherbicide for control of the invasive, aquatic weed. Scientists in the Crop Bioprotection Research Unit at the National Center for Agricultural Utilization Research, Peoria, IL, have developed a production and stabilization method for producing a stable form of MT, a microsclerotium. Field trials demonstrated enhanced hydrilla biomass reduction when microsclerotia of MT were applied with low dose rates of various chemical herbicides including fluoridone, endothall, diquat, or penoxsulam. Temperature studies with MT suggested that application at appropriate times of the year may enhance the potential for hydrilla control. 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.

Review Publications
Behle, R.W., Compton, D.L., Laszlo, J.A., Shapiro Ilan, D.I. 2009. Evaluation of soyscreen in an oil-based formulation for UV protection of Beauveria bassiana Conidia. Journal of Economic Entomology. 102(5):1759-1766.

Shapiro Ilan, D.I., Cottrell, T.E., Gardner, W.A., Behle, R.W., Ree, B., Harris, M. 2009. Efficacy of entomopathogenic fungi in suppressing pecan weevil, Curculio caryae (Coleoptera: Curculionidae) in commercial pecan orchards. Southwestern Entomologist. 34:111-120.

Shapiro Ilan, D.I., Cottrell, T.E., Mizzell III, R.F., Horton, D.L., Behle, R.W., Dunlap, C.A. 2010. Efficacy of Steinernema carpocapsae for control of the lesser peachtree borer, Synanthedon pictipes: Improved above ground suppression with a novel gel application. Biological Control. 54:23-28.

Jackson, M.A., Dunlap, C.A., Jaronski, S. 2010. Ecological considerations in producing and formulating fungal entomopathogens for use in insect biocontrol. Biocontrol. 55(1):129-145. DOI: 10.1007/s10526-009-9240-y

Avery, P.B., Hunter, W.B., Hall, D.G., Jackson, M.A., Powell, C.A., Rogers, M.E. 2009. Diaphorina citri (Hemiptera: Psyllidae) infection and dissemination of the entomopathogenic fungus Isaria fumosorosea (Hypocreales: Cordycipitaceae) under laboratory conditions. Florida Entomologist. 92(4):608-618.

Jackson, M.A., Dunlap, C.A., Jaronski, S. 2010. Ecological Considerations in Producing and Formulating Fungal Entomopathogens for Use in Insect Biocontrol. In Roy, H.E., Vega, F.E., Chandler, D., Goettel, M.S., Pell, J.K., Wajnberg, E., Editors. The Ecology of Fungal Entomopathogens. Dordrecht, The Netherlands: Springer. p. 129-146.

Jackson, M.A., Jaronski, S.T. 2009. Production of Microsclerotia of the Fungal Entomopathogen Metarhizium anisopliae and their Use as a Biocontrol Agent for Soil-Inhabiting Insects. Mycological Research. 113(8):842-850.

Vega, F.E., Goettel, M.S., Blackwell, M., Chandler, D., Jackson, M.A., Keller, S., Koike, M., Maniania, N.K., Monzon, A., Ownley, B., Pell, J.K., Rangel, D., Roy, H. 2009. Fungal entomopathogens: new insights on their ecology. Fungal Ecology. 2:149-159.

Last Modified: 3/1/2015
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