CongeladosNov. 4, 2011
Científicos de la Universidad de California se encuentran desarrollando una alternativa a la fumigación con bromuro de metilo
Scientists may have come up with a way to rescue the vast California strawberry industry from crop-killing pests, now that the long-used fumigant methyl bromide has been phased out for all but critical uses because it depletes ozone in the upper atmosphere.
Producing 85 percent of the nation’s strawberries, California growers have been casting about for alternatives to methyl bromide fumigation if they are to maintain yields. Strawberries are among the most valuable of all crops on a per-acre basis, but the popular fruit is beset with pests ranging from nematodes and other root eaters to aphids and whiteflies.
University of California scientists now report that use of totally impermeable film in strawberry fields can improve the effectiveness of a widely-used methyl bromide alternative known as 1,3-D (1,3, dichloropropene). Use of the film reduces the amount of 1,3-D needed to maintain yields, while lowering field emissions overall. The methyl bromide alternative, 1,3-D, can be used only in certain quantities, due to air quality concerns. In a recent trial, totally impermeable film (TIF) was laid out over Salinas fields to prevent the fumigant from leaking. The new film was compared with the standard film used by growers. Fumigant concentrations under TIF were 46 percent to 54 percent higher than under standard film, and the higher concentrations were correlated with higher strawberry yields and better weed control.
Emissions are a chief concern. Methyl bromide, a widely used fumigant in combination with chloropicrin, has been phased out since 2005 because it is an ozone-depleting substance targeted by the Montreal Protocol (a global treaty to control ozone depletion) and the U.S. Clean Air Act. However, it is still being used in some California strawberry fields under a critical-use exemption. Restrictions on the use of 1,3-D leave few other options for growers in key strawberry production areas near densely populated areas. TIF may ease some of the burdens of fumigant regulations on end-users, as well as ease concerns of the general public about exposure to fumigants, he concludes, the UC scientists say.