Bio-efficacy of Croton hirtus leaf and stem powders against Callosobruchus maculatus infestation on stored cowpea

Abstract

Background and aim: Croton hirtus L’Her (Euphorbiaceae), known as hairy croton, is popular in traditional medicine for the treatment of  hypertension, fever, inflammation, diabetes, amongst others.

Methods: Leaf and stem powders at concentration range of 0.2 – 2.0 g per 50 cowpea seeds, and standard insecticide, permethrin at 3.0  mg were used to dress cowpea seeds using standard method to determine their effectiveness in protecting cowpeas from attack by  weevils, Callosobruchus maculatus. Oviposition deterrency at 15 days after treatment (DAT) and inhibition of adult insect emergence at 50  DAT were assessed. Other parameters of seed damage were also investigated.

Result: Study indicated differences in the protective ability  of the leaf and stem powders on stored cowpeas. Both powders produced oviposition deterrency (greater for leaf, 73.6% at peak concentration) and adult insect emergence inhibition (greater for leaf, 84.61%) in a concentrationdependent manner. Efficiency of C.  hirtus powders was comparable to that of permethrin. All indices of seed damage witnessed diminution in a concentration-dependent  manner, and the leaf powder elicited greater percentage protective ability (48.7%) which was comparable with permethrin.

Conclusion:  Leaf and stem powders of C. hirtus examined for the first time, proved to be effective in protecting stored cowpea seeds from weevil  attack.