Integrated Control of Snap Bean Diseases Caused byPythiumspp. andRhizoctonia solani

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Abstract
In a 4-yr field study at Salisbury, Maryland [USA], an integrated control approach with cultural and chemical components successfully reduced snap bean diseases caused by the soil-borne plant pathogens Pythium spp. and R. solani. The major control component was plowing infested soil to a depth of 20-25 cm rather than disking to 5-7 cm before planting. This procedure alone generally increased plant stand and vine weight and always increased yield. Pod weights were increased 43-100% in each of 4 yr in the plowed soil. Chemical seed treatment with metalaxyl or metalaxyl plus chloroneb also increased plant stand and weight, but the magnitude of the increase was not as great as that achieved with plowing. In 3 of 4 yr, plowing in association with seed treatment gave a greater yield than that attained when each component was used individually. Preparations of fungal and bacterial biological control agents added in-furrow or to seed were ineffective in reducing disease when used individually or in combination with cultural or chemical methods. The inoculum densities of Pythium spp. and R. solani were less in plowed soils than in disked soils.