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Field and laboratory investigations were carried out during 2022-23 to study the bioecology and efficacy of plant extracts for the phytophagous coccinellid, Henosepilachna vigintioctopunctata (F.) for understanding them properly to devise ecology based management techniques. Besides damaging the brinjal a significant population of H. vigintioctopunctata beetle was recorded from the solanaceous weeds like Solanum nigrum and Physalis spp. Biology of H. vigintioctopunctata on S. nigrum under laboratory conditions was conducted and the results revealed that the beetle completed its life cycle in 23.1±3.5 days and the mean fecundity was 220 ± 33.0 revealing that the beetle can very successfully breed on this host plant. Morphological and taxonomical descriptions of the immature as well as adult stages of these beetles were studied and for proper identification the male genitalia was dissected. The population fluctuation of H. vigintioctopunctata in relation to weather parameters was also monitored under field conditions and was observed to have significant influence altogether on the pest population in brinjal but not in alternate hosts. The methanolic extracts of Polygonum hydropiper and tobacco decoction were found moderately effective in lowering the leaf damage by the beetle.
Selvaraj et al. (Wed,) studied this question.