Abstract:
The biological activity of neem oil and Neemazalon adult and immature stages of the larger grain borer, Prostephanus truncatus, as well as on its F1 progeny was assessed in stored maize in the laboratory. Repellency and persistency effects of the treatments in grain as well as the effect of the treatments on grain damage were also determined. Neemazal was more toxicto P. truncatus than neem oil. The highest dosage of 0.8ml/200g grain killed 100% adult P. maculatus after 72 h exposure but the same dosage of neem oil resulted in 70% mortality after 96h. The products also caused significant (p<0.05) mortality in P. truncates eggs and larvae, Neemazal provided greater protection to maize grains with no noticeable boreholes on grains' treatedwith 0.6 and 0.8ml/200g grain. All treatments repelled less that 50% P. truncatus adults. Activity of the two product significantly declined (0<0.05) in treated grain after 24 hour of storage following treatment. Neemaza loffered greater protection against both immature stages and adults of P. truncatusin stored maize.