In the present study, a screening was performed for 14 plant lectins in a binary choice bioassay against oviposition of cowpea weevil Callosobruchus maculatus (F.). Coating of chickpea seeds (Cicer arietium L.) with 0.05% (w/v) lectins tested of plant lectins resulted in a significant reduction in egg laying. The lectins tested can be classified into 5 groups: the lectins with complex specificity PHA and RPH scored 59-78% deterrent action; the mannose-binding lectins AMA, GNA, APA, ASA and PNA 66-74%; the N-acetylglucosamine binding lectins UDA and WGA 52-57%; the mannose-binding ConA 64%; the galactose/N- acetylgalactosamine binding lectins PNA, Jacalin and Morniga-G 37-64%, and the mannose/ N- acetylgalactosamine binding lectin TxLC-I 36%. In addition, it was shown that autoclaved lectin AMA and BSA were not active against oviposition, suggesting that carbohydrate binding activity of the protein plays an important role in the deterrent effect of the protein. All lectins (at 0.05%) showed a stronger effect on oviposition at a density of 20 C. maculatus adults as compared to 30. Further on, no significant effects were observed on adult development in the eggs deposition on the seeds coated with different lectins.
