Biological activity of two neem (Azadirachta indica A. Juss., Meliaceae) products on Hypsipyla grandella (Lepidoptera: Pyralidae) larvae

Biological activity of two neem products (Azatin and Nim 80) on mahogany shootborer (Hypsipyla grandella) larvae was studied. A randomized complete block design, with four replications, was used. H. grandella third instar larvae were exposed for 24h to Cedrela odorata leaf discs dipped in several treatment dissolutions of each formulated product (0.1, 0.32, 1.0, 3.20, and 10%); afterwards. each larva was transferred to a flask containing artificial diet, where it was allowed to complete its development. Variables measured included food consumption (foliar area eaten in 24 h), mortality, and developmental effects (developmental time for each larval instar and the pupa, and pupal weight). No one of the substances present in both products showed antifeedant activity on H. grandella larvae. Instead, Azatin caused quick direct toxicity and Nim 80 acted as a growth disruptant, especially at the three highest concentrations (1.0, 3.20, and 10%) in both cases. In the case of Nim 80, larvae died because they were unable to get rid of their exuviae, when molting to the 4th instar. (C) 2002 Elsevier Science Ltd. All rights reserved.