Prevalence and seasonality of insect pests in medicinally important plant Senna alata L. under tropical climate in the Coromandel Coast of India

摘要

An attempt is made to examine prevalence of insect pests and their seasonality in Senna alata L. from Puducherry region, India covering a period of one year. Totally, five insects found to make use of S. alata for ovideposition viz. butterfly (Catopsilia pyranthe ), Jewel bug (potamid Chrysocoris stoll i i ), flower bud worm (Hendecasis duplifascialis) Aphides (Aphis sp.), and Mealy bugs. All egg masses collected from leaves and flower buds are reared and developmental stages are documented. Secondly, two virulent borers viz. flower bud borer H. duplifascialis and pod borer Etiella zinckenella and their developmental stages are also documented for the first time in S. alata; thirdly, the extent of caterpillars that destroy medicinally important leaves of S. alata mostly young leaves, has also been documented. Adult insects viz. aphides (Aphis sp .) and green stink bug Acrosternum hilare, are also found feeding on leaves of S. alata . The last but unique observation made during field study is sighting of a worm inside anther for the first time. The seasonal study revealed that ovideposition is influenced by temperature and rainfall and showed higher level of ovideposition during late post-monsoon and early summer. The overall picture on association of insect pest with S. alata indicated a low level of insect pest faunal diversity. Present report would be considered as the important input into the annals of medicinally important member of the genus Senna .