DISEASE REDUCTION OF STRAWBERRIES VIA COVER CROPS AND ANAEROBIC SOIL DISINFESTATION, ALTERNATIVES TO FUMIGANTS
Miriam Olivera, Carol Shennan.
University of California, Santa Cruz, Santa Cruz, CA.
Large-scale strawberry production is limited by disease. Knowledgeable intensive management can prevent disease, yet fast treatments such as fumigants are favored though they pose environmental health risks. Anaerobic soil disinfestation (ASD) is a fumigant alternative method whereby carbon from plant debris is incorporated into soil saturated with water and covered by plastic mulch for 3 weeks. Anaerobiosis results in reduction of disease. The price of externally derived carbon, like rice bran, may increase due to scarcity driven by Californiaâ€™s ongoing drought and competing-use demands. Limitations may be remedied by growing rapidly maturing summer cover crops on site. They break the monoculture practices amenable to disease cycles. We hypothesize Sudan grass, wheat, no-cover crop, and +/- rice bran treatments will determine cover crop biomass production within 9 weeks through dry weight measure of C:N ratios. Cover crops, in combination with rice bran, will reduce pathogen numbers after ASD and will be assessed through culture methods. The soil microbial communities before and after ASD will change. This will be assessed through partial community analysis using T-RFLP and Q-PCR. Diseases such as crown and root rot will occur on all treatments and will be assessed through visual inspection of randomly selected plants and roots after harvest. The economics of treatments will be the same for all cover crops and different for no-cover crop. We will assess this through treatment cost and strawberry marketable yield. ASD and cover crop rotation may provide direct economic solutions to regulatory loss of fumigants, provide effective application of sustainability concepts to industrial agricultural settings, and contribute dialogue on the role of microorganisms in disease suppression.