Moldy Mayhem in Store for Sugar Beet Pest

By Jan Suszkiw
February 17, 2000

A beneficial fungus that ravages sugar beet root maggots could give farmers a new, natural defense against the pest.

Though it is under half-an-inch long, the maggot's assaults on sugar beet crops cost growers millions of dollars annually. Up to 38 percent of America’s sucrose for condiments, baked goods, and other products comes from the 1.5-million-acre sugar beet crop. Nearly half is treated with granular insecticides like chlorpyrifos to kill root maggots, offspring of the fly species Tetanops myopaeformis.

As they feed, maggots badly scar sugar beet roots, causing yield losses of 10 to 100 percent. Now, a new species of fungus--Syngliocladium tetanopsis--may help curb the pest's sweet tooth. Chris Wozniak discovered the fungus in 1994 and in September received a U.S. patent (#5,955,071).

His laboratory and field studies at the Agricultural Research Service indicate Syngliocladium’s spores can be sprayed or "seeded" into soils as a biological pesticide. Dormant until a maggot makes contact, the missile-shaped spores bore into their host’s body to germinate, destroying organs and tissues.

In petri dish experiments, this killed 95 to 100 percent of exposed, newly hatched maggots in three to five days. Eighty-five to 96 percent of older, final-stage maggots died after several weeks. Yet scientists didn't observe a similar fate in non-host insects, including beneficial lady bugs and lace wings or pests like Colorado potato beetles.

Wozniak’s chief colleague is Ann Smigocki, at ARS' Molecular Plant Pathology Lab in Beltsville, Md. ARS is the U.S. Department of Agriculture's principal research arm. Wozniak, now at EPA's Biopesticide and Pollution Prevention Division, continues collaborating with Smigocki.

They’re seeking a commercial partner to help develop the fungus into a biopesticide product that growers can use as an alternative to conventional insecticides. Coated onto beet seed, for example, it could be applied to soils where maggot-killing chemicals can harm non-target insects, or endanger groundwater. Use of the fungus, which doesn't infect plants, could also spare seedlings from phytotoxic harm caused by some insecticides.

Scientific contacts: Ann Smigocki, ARS Molecular Plant Pathology Lab, Beltsville, Md., phone (301) 504-5848, fax (301) 504-5320, [email protected]; or Chris Wozniak, EPA Biopesticide and Pollution Prevention Division, phone (703) 605-0513, fax (703) 308-7026, [email protected].


Story contacts
Jan R Suszkiw

U.S. Department of Agriculture
 


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