Cowpea beetle, Callosobruchus maculatus (Fabricius) (Coleoptera:
Chrysomelidae) is one of the most dangerous insect pests in field and storage. It
causes a high damage to the legumes by decreased dietary values, germination and
seed weights. Using synthetic insecticides for controlling stored grain pests have a
lot of problems for humans and environment. Therefore, the mixing seeds
laboratory experiments were conducted to study the efficacy of certain alternative
safety compounds against C. maculatus such as Beauveria bassiana, Metarhizium
anisopliae, ascorbic acid, boric acid, talc powder and kaolin compared with an
organophosphorus nervous insecticide, malathion 1% dust, that recommended in
Egypt for controlling stored grain pests. The present results showed that the
malathion was the highest toxicity effect against cowpea beetle adults with
LC50(3.89 ppm) after 3-day post treatment. However, the boric acid was the lowest
toxicity effect with LC50 (72855 ppm) after 6 days post treatment. The other tested
materials showed moderate effects. These results indicate that malathion is still
having high effect against cowpea beetle. The toxicity of bio-insecticides (M.
anisopliae and B. bassiana) after 6days were more than toxicity malathion 1%dust
after 1day.Wheraes, the toxicity of bio-insecticides (M. anisopliae and B.
bassiana) increased with increase of period of exposure from 2 to 6 days high rates
about 28 times, 31 times, respectively. The findings showed that the tested
compounds have a promising insecticidal activity against C. maculatus and can be
used as possible alternatives to synthetic chemical insecticides such as malathion
for the control of stored product insects.