California Strawberry Commission Continues Research to Improve Control of Soilborne Diseases

7/4/2014

The California Strawberry Commission has received a grant from California's Department of Pesticide Regulations (DPR) of $298,472 for a cooperative research project to investigate ways to improve control of soilborne diseases.

California strawberry farmers have invested significant funds in researching fumigant alternatives. Soilborne diseases harm the quantity and quality of a wide variety of crops in California, including strawberries, which affects farmers as well as consumers who value an abundance of healthy, locally produced fruits and vegetables. If untreated, studies show that soilborne diseases could cost Central Coast farm communities more than $1 billion annually in lost revenue.

Soilborne diseases are controlled with fumigants, which clean the soil before crops are planted to rid the soil of diseases and harmful pests. They are not sprayed nor applied on crops. Nearly half of the state's crops rely on fumigants to cleanse the soil before planting, but two of the most effective and widely used fumigants are no longer available to farmers in California because of increased regulations or pressure from activists.

The grant from DPR will investigate how to improve the effectiveness of an alternative soil treatment process, anaerobic soil disinfestation (ASD) which has shown some limited promise in laboratory and field tests in managing soilborne diseases, but with very inconsistent results. ASD consists of adding a large amount of plant material (such as rice bran at the rate of several tons per acre) to the field, covering the field with plastic, and then saturating the soil with water. The plastic remains in place for three to four weeks. The plant material decomposes and creates anaerobic conditions under the plastic. As the temperatures increase, the soil pH decreases, and the balance of organic acids and soil microbes shifts. These changes may suppress some soilborne diseases under some circumstances. This new research project will determine if using a small amount of a soil fumigant in combination with ASD could improve its effectiveness, reliability, consistency and cost.

In addition to the grant to the California Strawberry Commission, DPR awarded grants for research into alternatives to soil fumigation methods currently used by California pistachio and almond growers. Pistachio farmers use soil fumigants to control nematodes that reduce crop yields; almond orchards are often fumigated before the trees are planted to prevent damage from nematodes. The University of California Cooperative Extension, Merced County, received a grant from DPR for $74,384 for the pistachio research, and $108,433 for the almond research.

Please visit www.californiastrawberries.com for more information.