Effect of some plant oils as protectants of stored legumes against cowpea beetle, Callosobruchus maculatus (F.)‎ infestation

Abstract EN

Efficacy of four plant oils; almond, colocynth, sesame and castor bean, as protectants to cowpea and chickpea seeds against cowpea beetle, C.

maculatus was studied.

Mortality increased with the rise of oil concentration and exposure period.

All oils at 4, 6 and 8 ml/kg caused 100 % kill after 5 days from treatment, except castor oil on chickpea seeds which gave 96.6 and 98.3 % kill at 4 and 6 ml/kg, respectively.

No adult emergance was observed on cowpea and chickpea seeds at these rates, while at 2 ml/kg, a few number emerged.

LC50 treatments in all cases with almond, colocynth and sesame oils significantly reduced the number of eggs laid, % hatching, number of adults emerged, and weight loss percent; while castor oil gave complete inhibition of hatching.

All treatments at LC95 gave complete protection to seeds up to 2 months and significantly reduced the number of progeny after 4 months.

However, seed germination of the two legumes treated at LC95 significantly decreased after 4 months from storage compared with non-treated seeds.