New, cost-cutting approach to formulating pest-killing fungi

Jan 24, 2013 by Jan Suszkiw

Biopesticides containing beneficial fungi are often grown on grains or other solids, but U.S. Department of Agriculture (USDA) scientists have shown a liquid diet can work better.

The approach, dubbed "liquid culture fermentation," offers several benefits, including lower material costs and increased yields of certain forms of insect-killing fungi, including Isaria or Metarhizium, which can serve as biobased alternatives to .

For decades, biopesticide makers have grown such fungi on moistened grains or other solid materials to prompt them to churn out billions of specialized cells called "conidia," which penetrate the bodies of silverleaf whiteflies, aphids and other soft-bodied , killing the pests within a few days.

Over the past several years, however, scientists with USDA's Agricultural Research Service (ARS) have sought to improve on the practice by initiating liquid culture in special tanks called bioreactors. ARS is USDA's chief intramural scientific research agency.

According to Mark Jackson, a microbiologist with the ARS Crop Bioprotection Research Unit in Peoria, Ill., using liquid culture fermentation has significantly reduced production costs, especially those associated with nitrogen as a primary fungal nutrient. One nitrogen source, called hydrolyzed protein, is typically derived from agricultural commodities like milk casein, which can sell for more than $6 a pound. Liquid culture fermentation's use of less expensive nitrogen sources, including soybean flour or cottonseed meal, reduces the cost to 30 to 50 cents a pound.

Conidia have long been the spores of choice for biopesticide uses. But the researchers showed that other can be just as effective, including "blastospores" and "microsclerotia." The latter are clumps of pigmented fibers from which conidia can form. In laboratory tests, for example, conidia resulting from soil treatments of microsclerotia from the fungus M. brunneum killed 100 percent of sugarbeet root maggots, versus 25 percent killed for conidia-only treatments.

The flexibility of liquid culture fermentation to produce different types of fungal cells opens all sorts of doors in terms of where and when the pest-fighting microbes can be applied, according to Jackson.

Explore further: PacifiCorp Energy pleads guilty in bird deaths (Update)

More information: Read more about this research in the January 2013 issue of Agricultural Research magazine. www.ars.usda.gov/is/AR/archive/jan13/fungi0113.htm

add to favorites email to friend print save as pdf

Related Stories

Researchers tap yeasts as source of 'green' surfactants

Jul 28, 2011

Surfactants, which are wetting agents that lower a liquid's surface tension, have a long list of uses, from detergents and cosmetics to paints and pesticides. Most surfactants are petroleum-based. But in Peoria, Ill., a team ...

New fungi could curb grasshopper populations

Jan 07, 2011

(PhysOrg.com) -- Beneficial fungi that could help manage grasshopper populations are being tested by U.S. Department of Agriculture (USDA) scientists and university colleagues.

Collection Provides Supply for Taxonomical Rescues

Jan 25, 2010

(PhysOrg.com) -- The Agricultural Research Service maintains some of the world's largest publicly accessible collections of microbes that are used to benefit agricultural sciences. But some smaller ARS collections ...

Infrared sheds light on beneficial microbes

Dec 09, 2010

Infrared spectroscopy can quickly spot beneficial fungi on roots in soil, according to U.S. Department of Agriculture (USDA) soil scientist Francisco Calderon.

Fungus-on-Fungus Fight Could Benefit Chickpeas

Dec 08, 2009

(PhysOrg.com) -- The fungus Ascochyta rabiei threatens chickpea crops the world over. But now this blight-causing pathogen could meet its match in Aureobasidium pullulans, a rival fungus that Agricultural ...

USDA patents method to reduce ammonia emissions

Nov 01, 2012

Capturing and recycling ammonia from livestock waste is possible using a process developed by U.S. Department of Agriculture (USDA) researchers. This invention could help streamline on-farm nitrogen management ...

Recommended for you

Study finds tropical fish moving into temperate waters

Dec 19, 2014

Tropical herbivorous fish are beginning to expand their range into temperate waters – likely as a result of climate change – and a new international study documents the dramatic impact of the intrusion ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.