Epidemiology and management of soybean rust (Phakopsora pachyrhyrhizi)

Abstract

An experiment was conducted during 1999 and 2000 to study epidemiology, survival of rust Phakopsora pachyrhizi Sydow & Sydow in soybean [Glycine max(L.) Merr.] pathogen and its integrated management at Chhindwara district of Madhya Pradesh. Survival of rust pathogen in any form was not found during summers of 1999 and 2000, on any collateral host even in cool and humid areas of the state. Uredospores were the only spore form found on soybean which germinated at 18 degree-20 degree Celcius under laboratory conditions. The disease is favoured by moderate temperature (22 degree-25 degree Celcius), high rainfall and relative humidity in August and September. Two sprays of triadimefon (Bayleton @ 0.1%) were most effeetive, as these completely checked the rust infection and increased the yield (32%) over the control. Highest benefit: cost ratio (0.12) was observed under mancozeb (Indofil M-45,0.25%). Soil application of sulphur @ 20 kg/ha along with recommended dose of N P K (N 20 kg/ha, P2O5 kg/ ha 50 kg/ha and K2O 20 kg/ha) significantly reduced disease index (%) but farmyard manure with N P K resulted in maximum seed yield of 1.364 and 1.376 tonnes/ha at Chhindwara and Seoni respectively). Early sowing (June end) of the crop received lesser damage (36.15%) when compared with crop sown in mid-and end of July.