Off season management of field soil for control of castor wilt disease

Abstract

Castor (Ricinus communis) belonging to family Euphorbeaceae is cultivated throughout the world because of commercial importance of oil. India is the largest producer of castor oil. Wilt disease of castor caused by Fusarium oxysporum f sp ricini is a major disease in India often resulting in losses of more than 80% of crop yield necessitating interventions for its management. The objective behind this trial is to resort to deep ploughing in summer or soil solarization for 6weeks during peak summer with polythene sheet and application of Trichoderma as seed treatment and as soil application. Treatments viz (a) seed treatment with Trichoderma harzianum Th4d@10gm/kg seed (b) Seed treatment with T.harzianumTh4d@10gm/kg+furrow application of Trichoderma (c) seed treatment with carbendazim@2gm/kg seed and (d) control without Trichoderma and fungicide, imposed in solarized and non-solarized beds separately. Wilt incidence was recorded at 30 days interval till harvesting. In solarized plot, the wilt incidence was less compared to non-solarized plot. Seed treatment with Trichoderma showed 64.4% in solarized plot and 91% wilt incidence in non-solarized plots respectively. Seed treatment with Trichoderma and spot application near plant showed 55.3% wilt incidence in solarized plot and 96.7% in non-solarized plot. Seed treatment with carbendazim showed 70.5% wilt incidence in solarized and 93.7% in non-solarized plot. In control, 90.3% in solarized and 98.9% wilt incidence in non-solarized plots was recorded respectively.The inoculum load also reduced considerably from 10000-60000 cfu/gm of soil to 1000 to 1500cfu/gm of soil in all the treatments. It indicates that solarization is one of the best option for management of castor wilt disease.