author(s)
K Govindan, S Geethanjali, G Brundha and M Pandiyan

abstract
Laboratory studies were conducted at Department of Crop Protection, Agricultural College and Research Institute, Valavachanur – 606 753, Thiruvannamalai District to study the effect of various plant powders tested against, Callosobruchus maculatus (F.) Infesting stored black gram. Pulse beetle, C. maculatus are the most serious pests in stored legumes in majority of tropical countries. Attention has been given to the possible use of plant products or plant dry powders as promising alternatives to synthetic insecticides in controlling insect pests of stored products. Present study seven plant species evaluated for their bio activity to pulse beetle. The experiments were conducted on seven plant dry powders compared with untreated control. Among the plant powders evaluated by mixing with the seeds @ 2 percent w/w, among them results show Acorus calamus 2 percent rhizome powder was found to be significantly the best compared to other treatments and caused 100 percent mortality two days after treatment, which was followed by Solanum nigrum (37.77 %), Leucas aspera (18.88%), Cardiospermum helicacabum (21.11%) and Achranthes aspera (14.44%) and whereas untreated control recorded only 8.88 percent mortality was recorded. At six days after treatment highest mortality was seen S. nigrum (78.88 %) which was statistically on par with C. helicacabum (69.99%) and A. aspera (68.88 %) were observed and same trend was observed at 7 DAT. The experiment, on oviposition (egg laying) results showed that there was no egg laying in A. calamus 2 percent rhizome powder treated black gram seeds. The toxicity level different plant powders effect showed that Ocimum canum (42.44 eggs) > Solanum nigrum (47.66 eggs) > Coriandrum sativam (49.66 eggs) > Leucas aspera (72.33 eggs) > Achranthes aspera (81.66 eggs) as compared to untreated control (121.00 eggs) were laid. Complete inhibit of adult emergence observed in A. calamus than next to O. canum (16. 66), S. nigrum (26.66) and C. sativam (35.55) as compared with untreated control (100.66Nos) adult beetles were emerged. No seed weight loss was recorded in A. calamus at 30, 45 and 60 days after treatments. Next best plant powders reduce the seed weight loss in O. canum at 30 DAT (10.28%), 45 DAT(14.83%) and 60 DAT(19.24%) while, in 30.91 at (30 DAT), 35.25 (45 DAT) and 40.26 (60 DAT) per cent loss was registered. Different concentration of A. calamus experiment results concluded that all the four dose of A. calamus (0.50, 1.00, 1.50 and 2.00 %) highly effective against C. macultus viz., mortality, oviposition adult emergence and seed weight losses.