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An
experiment was conducted at the Entomology laboratory of Institute of
Agriculture and Animal Sciences (IAAS), Rampur in the winter of 2002/2003
with an objective to test the efficacy of nettle extracts to manage soybean
hairy caterpillar (Spilarctina casigneta Kollar). A total of forty-two
treatments including control (no nettle extract) and a positive check
(pesticide) were evaluated for their deterrent properties to the leaf-eating
caterpillar. Various extracts from the leaf of stinging nettle (Urtica
dioca) was prepared at Central Bio-chemistry Laboratory of IAAS. Leaf
discs of radish (Rahphanus sativus) having uniform size (1 mm 3) and weights
were treated with various extracts. Second instar larvae of Spilarctia
casigneta were allowed to take the treated leaf discs into 9 mm petriplates
upon starving them until 12 hours. The result indicated that nearly 30%
(out of forty two extracts) of the fractions extracted from chemical reagents
such as chloroform, ethyl acetate and hexane are found to posses some
sorts of antifeedant action to the larval development into the subsequent
instars. It has further indicated the possibility of exploiting nettle
extracts against biting and chewing pest insects indicating the ample
opportunity of integrating them into the development of organic pest management. |
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