CONSERVATION TILLAGE AND SEEDLING DISEASES IN COTTON AND SOYBEAN DOUBLE-CROPPED WITH TRITICALE

A double-crop rotation of cotton-triticale-soybean-triticale was grown for 4-5 yr in three experiments on loamy sand soil. Tillage treatments were conventional (moldboard plowing 20-25 cm deep after burning triticale residues), no-till, row-till, and ridge-plant. Triticale residues were managed by burning or cutting the straw short (20 cm) or tall (60 cm) at harvest. Population densities of Rhizoctonia solani anastomosis group (AG)-4 in soil after triticale were low to moderate and similar among treatments. Population densities of Pythium spp, in soil were high and variable among treatments. Root and hypocotyl disease severity in cotton and soybean seedlings was low to moderate each year. In most years and crops, tillage and residue management treatments did not influence seedling disease or inoculum densities of pathogens. When there were differences, burning triticale residues and moldboard plowing improved seedling health.