Root rot/wilt complex of soybean in Karnataka and its Management

Soybean Glycine max (L.) Merill is a protein rich oilseed crop. It is considered as a golden bean, miracle bean and wonder crop of the 20th century because of its characters and usage. Wilt/root rot is caused by Sclerotium rolfsii, Rhizoctonia sp. and Fusarium sp. are major constraints in soybean production. The studies on variability of the causal organisms were undertaken. Isolates of all the pathogens showed marked difference in their growth rate and time taken for sclerotial initiation and spore production. Cultural studies on different media revealed that S. rolfsii and Fusarium sp. grew well on Potato Dextrose Agar and Rhizoctonia sp. grew well on Sabouraud's Agar. Isolates varied in their growth in all the temperature tested. Maximum growth rate and spore germination was observed at 30C while no growth at 40C. In vitro and Glasshouse studies revealed that soil drenching with Carbendazim, Carboxin + Thiram, Thiophanate methyl, Hexaconozole, Neem oil, Nimbicidine, T. harzianum and T. viride helped to manage the disease successfully.