Efficiency of oils from medicinal plants as protectants of green gram against the pulse beetle.

Oils extracted from five medicinal plants were assayed for their ovicidal, repellent and
protectant properties against Callosobruchus chinensis L. infesting green gram Vigna
radiata (Wilcz). Per cent oviposition on seeds was significantly reduced when oils from
rhizomes of Acorus calamus and Curcuma amada, and seeds of Carum copticum and Bassia
longifolia were applied at doses of 0.25 and 0.50 ml/kg seed. Reduction in oviposition
on treated grains was mainly because of high insect mortality and repellency. Egg
hatching was also significantly lower at the tested concentrations. Oils of A. calamus
at 1 ml 'kg seed offered high degree of protection upto a period of 135 days, while oils
of C. amada and C. copticum at the above mentioned concentration protected the seeds
for 90 days only. Prolonged protection of green gram seeds was mainly due to reduced
oviposition, low hatching and high adult mortality. Germination of the treated
seeds with effective doses was not impaired to any significant extent.