Comparing the Effectiveness of Selected Cover Crops Incorporated as Green Manures without and with a Surface Seal Against Root Pathogens of Beans/Vegetables 2002
Type of grant: Cultural Methods / Biological Control
Project location(s): Findings are applicable nationally
Abstract: The incorporation of green manures of grain crops including wheat and sudangrass have been shown to reduce root rot diseases and their damage to beans and other vegetables. In addition, it was recently demonstrated that the incorporation of green manures of sudangrass suppresses the root-knot nematode and its damage to vegetables. The mechanism of nematode suppression was determined to be due to the production of toxic metabilites, including the hydrogen cyanide gas produced during decomposition of sudangrass tissues. Thus, this 2-year project was conducted to evaluate the efficacy of green manures of sudangrass and wheat with and without a surface seal against root rot pathogens and their damage to beans. The test was conducted in a research field with a history of continuous bean production and heavy infestation with root rot pathogens. Results obtained did not show a benefit from the incorporation of green manures of sudangrass or wheat as compared to the check treatments in reducing root rot severity or increasing yield. Also, sealing the soil immediately after the incorporation of the green manures did not result in better yield or reduced root rot severity. Additional cycle(s) of green manures application might be required before reduction in root rot severity and an increase in bean yield is realized in such heavy-textured soil and with high pathogen infestation.