Evaluation of Composts for Managing Phytophthora capsici 2002
Anu Rangarajan, Dept. of Fruit and Vegetable Science, Cornell
Margaret Tuttle McGrath, Dept. of Plant Pathology, Cornell
Dale Moyer, Cornell Cooperative Extension, Suffolk County
Type of grant:
Cultural methods; sanitation; physical controls
The goal of this long-term project is to evaluate commercially available composts for managing Phytophthora capsici on vegetables. This disease is very persistent in soils, and causes severe losses of both plants and harvestable fruit, under warm, moist conditions. Fungicides have only been moderately successful at providing control. A combination of good cultural practices and enhancing soil quality and disease suppressiveness is one strategy for management. In this project, we are trying to reduce the levels of disease in a research field that has a long history of Phytophthora. We are comparing the annual applications of compost to this field with the standard best management practices to determine if composts can suppress this disease. Compost is known to suppress other soil-borne diseases. Last year, we grew pumpkins on the plots, and all died form Phytophthora. One-year compost application did not suppress the disease. This year, we grew a non-susceptible crop, sweet corn, as part of the crop rotation. Compost did not supply significant amounts nitrogen to the crop, but did stimulate soil microbial activity. After a second compost application, soils were suppressive to another soil-borne disease, Pythium ultimum. Sweet corn yields were higher in composted plots, due to improved soil conditions but not excess nutrients. Tissue tests confirmed no difference in nitrogen content of leaves. Next season, snap beans will be grown in these plots. This crop is susceptible to other soil borne diseases that may be affected by compost amendments.