The powdered leaves of Annona senegalensis Pers., Hura crepitans L., Ricinus communis L., Eucalyptus camaldulensis Dehnh., Hibiscus sabdariffa L., Caesalpinus pulcherima L., Hyptis suaveolens Poit and powdered seeds of Khaya senegalensis Desr. A. Juss and Xylopia aethiopica Dunal were tested as protectants against fourth instar larvae of T. granarium. At the rate of 5% (w/w), powdered leaves of H. sabdariffa, C. pulcherima and E. camaldulensis (deoiled) had no contact toxicity on T. granarium larvae. In contrast, powdered leaves of A. senegalensis, R. communis, H. suaveolens, H. crepitans and powdered seeds of K. senegalensis and X. aethiopica significantly caused an increased mortality of the pest compared with the control. The effect of the plant powders were assessed on mean emergence of larvae and mean kernel weight loss after 12 weeks of storage. There was no significant difference between the most promising botanicals suggesting their relative potential for use in the control of T. granarium larvae.
Musa et al. (Thu,) studied this question.