Strawberry Farmers Look for Fumigant Alternatives

Mar 8, 2012


As regulations tighten on pesticide use, and the buffer between urban areas and farmland shrinks, strawberry farmers are searching for alternatives to fumigants. 

In a strawberry field with near Watsonville, rows of raised beds are wrapped tight in plastic. This common practice helps keep strawberries out of the dirt, and conserves water by keeping the soil moist.  But the strawberries in this field aren’t growing in soil.  They’re growing in soil alternatives including combinations of compost, the fiber from coconut husks and something called peat.  “ In Scotland they use it to dry the barley that gives you the flavor for scotch comes from peat. So if you go to a garden center you see bags of sorghum moss, which is peat,” said Dr. Dan Legard, Director of Research for the California Strawberry Commission.  In this field, the commission is searching for alternatives to fumigants, which conventional strawberry growers use to pre-treat soil. “The challenge with soil is it harbors pathogens.  When you grow a crop like strawberries, there’s very short rotations because of the value of our crop.   Lack of the rotation partners, pathogens build up in the soil, and so when you use soilless media, you avoid that pitfall,” said Dr. Legard.  So far, peat is proving to be the best soil alternative, but it’s too expensive. So they’re testing other media and various mixtures of peat. To help the research continue, the California Department of Pesticide Regulation is bringing $500,000 to the project.


“How do we grow strawberries in areas that have restrictions where you cannot use fumigants,” said Brian Leahy, DPR Director.  Leahy is referring to farmland in buffer zones, which can be near houses or schools, where farmers could grow strawberries if they didn’t use fumigants.   He says the space between agricultural land and urban areas is shrinking.  “People who are not part of the agricultural community have a different acceptance of what they want to have in their environment.  If we are going to keep agriculture in California, we are going to have to deal with this urban edge,” said Leahy. 


Another reason to find alternatives is methyl bromide. It’s a common fumigant used by strawberry farmers, but it’s being phased out because of its impact on the o-zone layer.  A replacement is methyl iodide, which has its own problems.  Scientists have said it can cause cancer, and it’s at the center of a lawsuit trying to prevent its use in the state.  The judge is expected to rule soon.  “We are going to watch and see what the judge tells us to do.  And then with all the chemicals and all the pesticides that the department oversees, there is  a continuous reappraisal, so that is a tool that we have on every pesticide,” said Leahy. 


The research project exploring fumigant alternatives continues for the next three years.  Farm scale testing could begin as early as next year.