Author(s):

Shail Bajpai and BS Chandel

Abstract: Laboratory trials were conducted to assess the insecticidal activities of naturally occurring indigenous extract and their formulations against Diacrisia (Spilosoma or Spilarctia) obliqua Walker. The experiment was done in three glass jar (23cm x 10cm) and replicated thrice by using each selected extractive per jar. For testing, the Brassica juncea ver. varuna leaves were used as food. B. juncea ver. varuna leaves were cut and sprayed the extracts of different concentrations for two minutes. The treated foods were kept in jar on moist filter paper. The treated leaf pieces were dried under clip and left under electric fan for an about half hour to make a dry film of the extracts on the leaves for each set of extract. Now, 24 hours starved laboratory reared third instars ten larvae were released in each treatment and each treatment replicated thrice. For control the leaf pieces were dipped in Benzene +emulsified water only. After 6, 12 and 24 hours, the data was collected on the larval mortality on treated food and mortality over control was recorded. The result indicated that alcoholic extracts of A. maxicana registered highest mortality (70.07%) to the larvae of D. obliqua when compared to other plant extractsshowed as: A. indica (63.93%) and B. frondosa (63.90%), have registered encouraging (greater than 60% mortality) results having insecticidal properties. Consistently, remaining all these aforementioned plant extractives has revealed their insecticidal potential at various intervals.

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