Scientists search for alternatives fumigant

Tuesday, June 25, 2002

ATTAPULGUS, Ga. -- In small plots of Southern peas, growing in the sandy soils near Georgia's southwest corner, horticulturists Darby Granberry and Juan Carlos Diaz-Perez are evaluating the potential of compost for controlling pests that gnaw at farm income.

They are trying to find a product that could help replace methyl bromide -- a cheap, lethal and effective soil additive that farmers have used for half a century to control insects, nematodes, weeds and pathogens in more than 100 crops, including tomatoes, peppers, eggplants, strawberries, almonds and watermelons.

But methyl bromide also depletes the ozone, and farmers in industrialized nations won't be able to use it after 2005. So scientists around the world, including Granberry and Diaz-Perez, are searching desperately for replacements for the soon-to-be-banned fumigant. Compost might be able to do some of methyl bromide's jobs.

"It has worked in other parts of the country," said Diaz-Perez. "It has worked under greenhouse conditions. We want to test it under field conditions."

Scientists have been working on alternatives since the Environmental Protection Agency announced the phase-out in 1994. Most think it will be impossible to find one product that replaces methyl bromide.

The alternatives studied have included compost, other pesticides, beneficial fungi, steam-cleaning the soil and pasteurizing it with solar heat, or solarization. But none seem to fit.

"Because of the time frame in phasing out methyl bromide, it has been a frantic search," said Gary Obenauf, a Fresno, Calif., agricultural consultant who chairs the annual Methyl Bromide Alternatives Conference. "We haven't been able to find a silver bullet -- a one-on-one replacement for methyl bromide."

Granberry, Diaz and others are conducting a three-year test to determine whether the addition of compost provides some of the benefits of methyl bromide. Compost, which enhances plant growth and increases biological activity in the soil, could mean more beneficial microorganisms for pest control.

"We want to get the good guys in there, but we can't say it happens until it happens," said Granberry.

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