B.A. College of Agriculture, Gujarat Agricultural University, Bio-Control Unit, Department of Entomology, Anand Campus, Anand-388110, Gujarat, (India).
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The biology of Eublemma scitula Ramb, an important predator of scale insect, Suissetia coffeae Wlk., a serious pest of pointed gourd was studied at Anand campus of Gujarat Agricultural University during 1985 and 1986. Eggs of the predator were laid singly and hatched in 4–6 days. The average incubation period during winter, summer and under controlled conditions (26.7°C ± 1.1°C and 63.67% relative humidity) were 5.29, 4.80 and 4.95, respectively. The durations of three larval instars at 26.7°C ± 1.1°C and 63.45 per cent R.H. were 4.1, 4.4 and 11.7 days, respectively. At ambient temperature during winter and summer, the durations were 4.5, 4.7, 11.8; and 3.2, 3.3, 9.1 days, respectively. All the larval stages were predatory on scale insect and consumed on an average 18.05 mature female scales, the maximum being 22 during the larval period. There was a short prepupal stage of 3.7 days at 26.7°C ± 1.1°C and 65.40 per cent R.H. During winter and summer, the average prepupal period was 5.7 and 3.3 days, respectively. The average pupal period at 26.7°C ± 1.1°C and 65.91 per cent relative humidity was 10.9 days. During winter and summer, the pupal period was 17.1 and 13.6 days, respectively. The predator was found to undergo hibernation in its prepupal stage during November–December and remained quiescent until March–April. The adults are small sized moths, highly pigmented on their forewi.ngs, more in female. The female and male with their wing expansion measure 15 to 18 mm and 13.5 to 16.5 mm, respectively. The sex ratio in the laboratory conditions was 1:0.96 (male: female), while it was 1:0.94 in the field condition. The average pre-oviposition, oviposition and postcoviposition periods were 1.2 ± 0.107, 4.4 ± 0.445 and 2.5 ± 0.363 days, respectively. The maximum fecundity was 195 with an average of 91.73 ± 14.70. The average longevity of ovipositing female was 8 ± 0.61 days and 7.2 ± 0.43 days in male. The entire life cycle was completed in 58.25 and 45.96 days for the fcmale, and 57.59 and 44.01 days for the male during winter and summer, respectively. This suggests that the development is delayed at low temperature in winter than the summer. In controlled conditions, it was 48.50 and 46.91 days for female and male, respectively. No hyper parasite was recorded on Eublemma in this area.
