Use of bioagents in the management of black scurf of potato

Potato (Solanum tubersum) is a unique crop which can supplement the food needs of the country in a substantial manner. Potato tubers are susceptible to infection of almost of potato pathogens, but. Black scruf caused by Rhizoctonia solani Kuhn is of world wide occurrence. It deteriorates the quality of potato tubers and presence of sclerotia on tubers help in introducing the disease in a disease free field. In the present study, an attempt was made to evaluate the effectiveness of bio-agents like Trichoderma harzianum, Trichoderma viride and Pseudomonas fluorescence @ 15 g and 20 g as tuber dip as well as spray on infected potato tubers before sowing to manage the black scurf. The study revealed that spraying of Trichoderma harzianum suspension @ 20 g/lit showed maximum (48.66 cm) growth of potato plants followed by Pseudomonas fluorescence 20 g/lit (46.16 cm) over untreated control. However, maximum disease control was recorded in Pseudomonas fluorescence and Trichoderma harzianum @15 g/lit and 20g/lit, when used as tuber dip and by spray method. The method of application did not affect the disease severity. Trichoderma harzianum @ 20 g/litre as spray resulted in maximum tuber weight (660 g/pot) followed by Pseudomonas fluorescence (480 g/pot) when used @ 15 g/litre and 20g/litre as spray method as compared to untreated control. Comparatively, recommended fungicide Emisan @2.5g applied as seed tuber dip treatment also provided good disease control but the tuber weight (400g) per plot was lower than bioagent treatments.