Effect of plant lectins on larval development of the legume pod borer, Maruca vitrata

The legume pod-borer Maruca vitrata (Fabricius), [Lepidoptera: Pyralidae] i s a major constraint restricting increased cowpea production in tropical Af rica and Asia. Since lectins are known to have insecticidal properties agai nst several pests, a survey was undertaken to screen for the effects of 25 lectins from 15 plant families on the development of Maruca pod borer (MPB) larvae. The list included 8 galactose/N-acetylgalactosamine-, 7 mannose-, 5 complex glycan-, 2 sialic acid- and 3, N-acetylglucosamine-specific lecti ns. Feeding bioassays using artificial diet were carried out at 2% (w/w) to pical levels. Although a total of 16 lectins had detrimental effects pertai ning either to larval survival, weight, feeding inhibition, pupation, adult emergence and/or fecundity, only the Listera ovata agglutinin (LOA) (Orchi daceae) and Galanthus nivalis (Amaryllidaceae) agglutinin were effective ag ainst MPB larvae for all six parameters examined. Larval mortality and feed ing inhibition caused by the most active lectin (LOA) was above 60%.