Department of Entomology, Orissa University of Agriculture and Technology Bhubaneswar-751 003, Orissa (India).
Nisaga simplex Walk. is a defoliating pest of wet season rice. Its life stages were studied at two locations, viz, Regional Research Station, Bhawanipatna; and the Department of Entomology, Orissa University of Agriculture and Technology, Bhubaneswar (India) during 1986 to 1988. The emergence of moth took place during 3rd and 4th week of June after monsoon break. The breeding was observed on the grasses growing on the bunds of rice field. The moth laid eggs (246.8 ± 24.44) on either side of the grass blades. Egg stage lasted for 8.1 ± 0.73 and 6.9 ± 0.73 days at Bhawanipatna and Bhubaneswar, respectively. The mean duration of different instars, viz., Ist, IInd, IIIrd, IVth, Vth, VIth, VIIth and VIIIth, at Bhawanipatna and Bhubaneswar was 6.9 and 6.7, 7.3 and 7.2, 7.7 and 7.4, 8.1 and 8.7, 8.6 and 8.2, 9.0 and 9.6, 10.8 and 12.7, and 13.2 and 16.1 days, respectively. It completed eight larval instars in 71.6 ± 2.36 and 76.6 ± 7.32 days at these two locations, respectively. It pupated in the field bunds at a depth of 5–18 cm from the ground level. The pupal period continued from 263 to 274 days. The pupa metamorphosed to adult after monsoon shower of the next year. The total life cycle lasted for 351.5 ± 2.58 and 360.2 ± 7.42 days at Bhawanipatna and Bhubaneswar conditions, respectively. Males can be differentiated from Ule females by their bipectinate antennae. The females possess filiform type.
