Background Botanical pesticides may be a possible solution to the post-harvest loss of stored grains faced by farmers and food processors. In this study, seed preservatives properties of Secamone afzelii leaves extracts at 50, 100, 150, 200 µl concentrations were investigated against lesser grain borer Rhyzopertha dominica (Fabricus) infestation on wheat grains weight loss and seed germination capability arranged in a Completely Randomized Design (CRD) and replicated thrice under ambient laboratory conditions. Results The outcomes of the study showed that S. afzelii leaves extracts exhibited significant effect (p < 0.05) in suppressing R. dominica adult emergence and weight loss of wheat grains than untreated. The increase in the concentrations led to significant decrease in adult emergence and weight loss with different extracts. Secamone afzelii ethyl acetate and hexane extracts significantly subdued adult emergence in contact toxicity (6.69% and 8.49%) and fumigant toxicity (8.85 and 8.87); a similar trend was observed in weight loss in both contact (2.33% and 5.13%) and fumigant (1.50% and 1.03%) toxicities at 200 µl, respectively. None of the extracts hinder the germination of treated grains, while germination percentage ranged between 88.69% and 93.40%. Conclusion The results clearly indicated that S. afzelii extracts, in general, ethyl acetate and hexane extracts of S. afzelii in particular were the best seed preservative for stored wheat. Thus S. afzelii leaves extracts could be utilized as grain protectant substitute for conventional synthetic insecticides and fumigants in the control of insect infestation and conservation of stored grain quality and germination capability. Further study is required to identify the bioactive chemicals responsible for the S. afzelii extracts insecticidal activity and stored grains quality preservation.

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The efficacy of Senna occidentalis leaf powder against Callosobruchusmaculatus (F) on cowpea treated seeds was evaluated under ambientcondition (32±0.64°C and 68±3% R.H.) at the laboratory of AgriculturalTechnology of Rufus Giwa Polytechnic, Owo. C. maculatus was obtainedfrom Oja‐Oba market, Owo, Ondo State of Nigeria. The insects were rearedand bred in the laboratory. The cowpea seeds used for the bioassay werekept in the freezer for 15 days to eliminate infestation from the field. Theleaf powder was obtained after milling and four dosages of the powder (0.5,1.0, 1.5 and 2.0g) were separately admixed with 20g of cowpea in separatepetri dishes. Ten pairs of C. maculatus were introduced into each petri‐dish.Number of adult mortality, egg laid, percentage egg hatching, adultemergence and weight loss from each treatment were compared withcontrol treatment. It is concluded that the Senna occidentalis contains toxicproperties valuable for the control of C. maculatus.