Natural Biocontrol Agents of Aeginetia pedunculata (Roxb.) Wall. (Orobanchaceae), a Root Holoparasitic Angiosperm of Sugarcane

摘要

Root holoparasitic angiosperm, Aeginetia pedunculata (Roxb.) Wall. (Orobanchaceae) causes wilt disease in sugarcane around sugar factory areas at Plassey, West Bengal. Periodic surveys in the infected sugarcane plots revealed the occurrence of two insect herbivores, Spilosoma obliqua and Gonocephalum depressum and two fungal pathogens, Fusarium oxysporum and Erysiphe cichoracearum on A. pedunculata. It was estimated from field observations that these insect and fungal species reduced seed capacity of A. pedunculata by 25.1, 88.5, 80.0 and 50.9%, respectively. Though the insect species are polyphagous and the fungal pathogens are polytrophic in nature, these were found to reduce the seed production capacity of the root parasitic angiosperm causing wilt disease in sugarcane. A suitable strategy for enhancing the activities of these agents in nature and studying the specificity of F. oxysporum and E. cichoracearum to A. pedunculata may lead to the management of this parasitic angiosperm in the sugarcane ecosystem.