Bionomics of the jute hairy caterpillar, Spilarctia oblique (order: Lepidoptera, family: Arctiidae; walker) of Corchorus olitorius jute


Md.N. Islam, Md.S. Polan, S. Ahmmed and Md.S. Rahman*

Background and objective: Jute hairy caterpillar is one of the most serious polyphagous and widely distributed insect pests causing damage to a large number of cultivated as well as non-cultivated plants species. It is urgent to know the biology of a pest if we want to control that pest. So, a research work was taken to study the bionomics of Jute hairy caterpillar.

Materials and methods: The research work was conducted in Completely Randomized Design (CRD) with twelve replications. Larvae of Jute hairy caterpillar, Spilarctia oblique were collected from the jute field and reared in the rearing insect box. Old leaves and exuviate were cleaned every day and records on moulting maintained regularly. After emergence, the adults were allowed to mate in the potted jute plants which were covered mosquito net. Data on moulting, larval and pupal period, growth stages were carefully taken.

Results: The incubation period varied from 4 to 7 days with an average of 5.17 ± 0.270 days. The length and width of pupae were found with an average of 17.25 ± 0.217 and 5.375 ± 0.164 mm respectively. The duration of first, second, third, fourth, fifth and sixth instar was found with an average of 2.83 ± 0.67, 5.25 ± 0.278, 7.92 ± 0.228, 10.83 ± 0.33, 16.42 ± 0.312 and 19.75 ± 0.304 days respectively. The total larval period was ranged from 17 to 22 days with an average of 19.91 ± 0.47 days. The total life span of male and female was found 37.99 ± 0.55 and 41.41 ± 0.49 days respectively.

Conclusion: The results showed that the biology of jute hairy caterpillar indicates the different stage of this insect. Further research is highly recommended for more accuracy of the result.

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