STUDIES ON THE MASS PRODUCTION TECHNOLOGY OF MENOCHILUS SEXMACULATUS FABRICIUS (COLEOPTERA:COCCINELLIDAE) AN IMPORTANT PREDATOR OF APHIDS
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Date
1996
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AAU, Anand
Abstract
Studies on the mass production technology of Menochilus sexmaculatus (Fabr.) (Coleoptera : Coccinellidae) were carried out during 1993 to 1995 at Anand Campus of Gujarat Agricultural University. Results revealed that A. craccivorci (Koch.) can be mass reared throughout the year by conveyer supply of 17 days old 20 cowpea plants In a medium sized earthen pot (14 cm high X 17.5 cm diameter) charged with 800 A. craccivora and by keeping the pots in a field cage (covered with shade net during winter and hessian cloth moistened during summer). On an average 4019.67 aphids/pot could be produced. Mean temperature ranging between 20.88°C to 28.98°C, relative humidity of 54.40 to 66.02 per cent and photoperiod of 8.08 to 9.33 hrs during October to January were very conducive for the development of aphid. The high temperature (31.95°C to 32.19°C) and high relative humidity (88.78 to 89.57 per cent) and photoperiod of 5.18 to 10.46 hrs during May-June were also very conducive for the aphid multiplication. For mass production of M. sexmaculatus on insectary reared A. craccivora and field collected Aphis gossypii (Glov.), two phase rearing (Rearing the larva for first three days in group of 100 and then in isolation) was found effective larval rearing method in terms of better pupal recovery, adult emergence, fecundity and labour. Egg predation by the adult M. sexmaculatus was Q, found to be a limiting factor in its production technology. To overcome the same it was found that overcrowding of the adults should be avoided. A maximum of 5 mated females can be accommodated in a three liter capacity transparent plastic jar. This reduced the egg predation to the tune of 12.93 per cent and without any significant effect on the per cent hatching. The loss in the egg predation can be further reduced by collecting the eggs at 7 hrs, 13 hrs and at 20 hrs from the oviposition cage, when most of the eggs are deposited by the females. The gentle removal of eggs from the oviposition site did not affect the hatchability of the eggs. The fresh eggs could not be stored at 7+1°C in freez for more than one day. Fresh pupae could be stored for 8 days without adversely affecting the emergence of the adult (86.38 per cent emergence) at 7+1°C in freez, while fresh adult could be stored for 22 days with 28.99 per cent mortality . No noticeable change in fecundity was observed when the predator was reared upto three generations on A. craccivora Honey bee. Apismellifera(L.) larvalor pupal powder based diet for adults was found good substitute to natural aphid prey. The female, when fed on this diet laid on an average 69.89 fertile eggs and lived for 42.78 days. The male longevity averaged 33.55 days.
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AGRICULTURAL ENTOMOLOGY, AGRICULTURE, A STUDY