Model Bioinsecticide Aimed at High-Value Crops

By Ben Hardin
January 8, 1999

WASHINGTON, Jan. 8--U.S. Department of Agriculture scientists are fine-tuning a friendly fungus that attacks silverleaf whiteflies and other pests and could be the foundation of a new bioinsecticide service industry. Silverleaf whiteflies alone cause multimillion-dollar crop losses each year to U.S. cotton and many fruits, vegetables and ornamentals.

Work with the environmentally friendly fungus Paecilomyces fumosoroseus is under way at the National Center for Agricultural Utilization Research, operated at Peoria, Ill., by USDA’s Agricultural Research Service. The ARS scientists say factories could produce P. fumosoroseus, dry it and transport it to small fermentors at field sites. There the fungus would be rejuvenated, multiplied and applied through spray or irrigation systems.

“It seems fitting that scientists in the same center that helped launch the antibiotics industry a half-century ago should partner with industry to harness fermentation technology for our nation’s agriculture,” said Floyd Horn, ARS Administrator.

About 3 years ago, NCAUR microbiologist Mark A. Jackson and his colleagues applied for a patent on mass-producing the fungus. The invention was a modified version of deep-tank fermentation developed at the center to mass-produce penicillin during World War II.

In recent years, the researchers have steadily improved P. fumosoroseus fermentations, doubling the number of spores produced in a tank and cutting fermentation time from three days to less than two. In the process, they developed fermentation mixtures that are more economical than the precisely defined recipes used earlier.

For factory-produced fungi to become commercially viable, large and predictable numbers of healthy spores must be produced and dried months in advance. In recent laboratory studies, the scientists found about 75 percent of freeze-dried spores remained alive after five months of storage.

To lower bioinsecticide costs, the researchers are defining conditions that allow the fungus to multiply rapidly in portable fermentors. As the research progresses, they will inoculate fermentors at several ARS locations and commercial field sites. The ARS scientists at Peoria are using a portable fermentor patented by Eco Soil Systems, Inc., San Diego, Calif., under a three-year cooperative research and development agreement (CRADA) begun last summer with the company.

Small packages of well-maintained, freeze-dried spores will be mixed with nutrients in the fermentors. The spores are expected to spring vigorously from their Rip Van Winkle state and multiply 100- to 1,000-fold. These fresh, active spores will then be sprayed directly on plants to kill whiteflies.

Technologies for P. fumosoroseus may later be adapted to different fungi suited to protecting turf grasses from insects. Companies that provide care for lawns and golf courses could then provide more environmentally friendly pest controls.

More information about the research is available on the World Wide Web at:

/is/AR/archive/jan99/tank0199.htm

Scientific contact: Mark A. Jackson, ARS National Center for Agricultural Utilization Research, Peoria, Ill., phone (309) 681-6283, fax (309) 681-6427, jacksoma@mail.ncaur.usda.gov.