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Superb Strawberries--Without Help From Methyl Bromide

Most of the bright-red, juicy strawberries produced in this country are plucked from plants growing in soil that's been fumigated with one of the world's most effective farm chemicals, methyl bromide. The compound zaps soil-dwelling organisms that might otherwise weaken or kill berry plants. But methyl bromide use is being phased out because of evidence that the compound depletes the Earth's ozone layer.

At research laboratories in Davis, Fresno, and Salinas, Calif., ARS scientists are scrutinizing environmentally friendly alternatives to methyl bromide. Soil scientist Husein A. Ajwa and agricultural engineer Thomas J. Trout at Fresno, for example, are using irrigation lines--called drip tapes--to deliver candidate fumigants to strawberry fields.

The two researchers have probably explored more variations of that idea than any other recent scientific team. The grower-sponsored California Strawberry Commission is funding part of this research. Applying fumigants through drip irrigation systems, says Ajwa, may reduce worker exposure to the chemicals and may also decrease the amount of chemicals needed to treat the fields. Among the best performing of the compounds that Ajwa and Trout have examined is InLine. At some sites where InLine was applied, marketable yields of strawberries were 95 to 110 percent of those from plots treated with methyl bromide in combination with another compound, chloropicrin.

InLine is made up of about 60 percent 1,3-dichloropropene and about 35 percent chloropicrin. The manufacturer, Dow AgroSciences LLC, is seeking federal and state approvals for use of InLine in strawberry fields.

An article in the January issue of ARS' monthly Agricultural Research magazine tells more.

ARS is the U.S. Department of Agriculture's chief research branch.

Scientific contact: Husein A. Ajwa, ARS Water Management Research Laboratory, Fresno, Calif.; phone (559) 453-3105, fax (559) 453-3122, hajwa@asrr.arsusda.gov.