In-vitro efficacy of Verticillium lecanii (Zimm.) Viegas against Estonian cyst nematode , Cactodera estonica

摘要

Cactodera estonica is a cyst forming plant parasitic nematode, recently reported from two important world biodiversity hotspots such as Nilgiris and Himalayan Biospheres of India. It poses a serious threat to the biodiversity of both the biospheres. Therefore, in the present study, efforts were made to evaluate the in-vitro efficacy of an entomopathogenic fungus Verticillium lecanii isolate (ITCC 7084) against C. estonica . The effect of different treatments viz ., T1-10%, T2-20%, and T3-30% cell suspension of 1.7 × 10~(5)CFUs of V. lecanii isolate was observed against cysts and eggs of C. estonica at 8, 24, 48, and 72 h after inoculation (HAI). The fungal isolate was found very effective and acted very fast against cysts and eggs of C. estonica . Within 24 h the growth of fungal mycelium was noticed on the cyst, however, at 48 and 72 HAI, significant differences were observed between the disintegration of the cysts and eggs inside the cyst in fungal treatments compared to untreated control. The percentages of leftover eggs and cysts were found inversely proportional to the concentration of V. lecanii and the duration of exposure. The present study concluded that V. lecanii isolate (ITCC 7084) is highly effective against C. estonica and can be utilized for its management in the future. Further, the studies should also focus on identifying enzymes responsible for the disintegration of the cyst wall and eggshell; in addition to this, the field efficacy of the isolate should be tested before its inclusion in the integrated nematode management program.