Comparative effects of some botanicals for the control of the seed weevil Caryedon serratus Olivier (Col., Bruchidae)

Abstract

Comparative efficacy of eco-friendly botanicals extracted from leaves and seed kernel of Azadirachta indica A. Juss (neem) and Eucalyptus camaldulensis Dehn was tested against the noxious weevil Caryedon serratus Olivier. Leaf powder, seed kernel powder and oil extracted from the seeds of A. indica and leaf powder and oil extracted from the leaves of E. camaldulensis and benzene hexachloride (BHC) were tested at 1, 3 and 5% (w/w or v/w) against C. serratus. Eucalyptus leaf oil (ELO) and neem oil (NO) at 3 and 5% were as efficient as BHC and significantly (P = 0.0001) reduced egg laying by C. serratus, whereas Eucalyptus leaf powder (ELP) had no significant effect. Neem seed kernel powder (NSKP) at 5%, ELO (3 and 5%) and NO (3 and 5%) significantly (P = 0.0001) reduced egg hatching more than BHC at all doses. NO (3 and 5%) and ELO (3 and 5%) significantly (P = 0.0001) reduced larval development more than BHC, whereas ELP and Neam Leaf Powder had no significant effect. Adult emergence and mortality were also significantly (P = 0.0001) affected by some botanicals tested, especially oils. Oils were more effective as compared with powder. The study indicated that the botanicals tested have a good potential in replacing conventional pesticides because of their high efficacy and environmental safety.