BIOLOGY, POPULATION DYNAMICS AND MANAGEMENT OF HELICOVERPA ARMIGERA ARMIGERA (HUBNER) INFESTING 'KALMEGH' ANDROGRAPHIS PANICULATA NEES. UNDER MIDDLE GUJARAT CONDITION
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Date
2001
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AAU, Anand
Abstract
Investigation on biology, seasonal incidence of H. armigera armigera and its natural enemies and management of H. armigera armigera infesting A. paniculata in middle Gujarat condition were carried out during idiarif 2000-2001 at Department of Entomology and Medicinal and Aromatic Plants Farm, Gujarat Agricultural University, Anand. The study on biology of H. armigera armigera on pods of A. paniculata indicated 3 days incubation period while larval period was 29.68 ± 0.85 days (d) for male and 29.92 ± 0.9d for female. The pre-pupal period was 3.04 + 0.54d for male and 3.02 + 0.38d for female whereas pupal period was 20.12 + 1.13d for male and 19.85 + 1.25d for female. The adult duration was 5.4 + 0.83d for male and 7.13 + 1.5d for female. The total life span was 60.79 + 1.19d for male and 62.67 + 1.18d for female. The pre-oviposition, oviposition and post-oviposition periods were 3.2 + 0.5d, 2.8 + 0.56d and 1.0 + 0.53d respectively. The fecundity was 52.66 + 26.13 eggs/female. The larval survival for male and female was 18 per cent and 20 per cent respectively whereas growth index was 0.54 for male and 0.67 for female. The study on survey of H. armigera armigera and its natural enemies infesting A. paniculata revealed that ovipositional and larval activity was observed from 3rd week of October 2000 to 1st week of January 2001. No significant correlation was found between ovipositional and larval activity with any of the weather parameters. The activity of larval parasitoid Campoletis sp. (Ichneumonidae : Hymenoptera) was found from 2nd week of November to 1st week of December ranging from 3.13 to 12 per cent with maximum per cent parasitism (12) observed during 3rd week of November while the activity of larval pupal parasitoid Carcelia sp. (Tachinidae : Diptera) was found from 3rd week of November to 4th week of December ranging from 3.85 to 9.52per cent with maximum parasitism (9.52 %) observed during 2nd week of December. The studies on management of H. armigera armigera infesting A. paniculata indicate that significantly low oviposition and low larval population was observed in IPM modules over control. More eggs and larvae were observed on marigold than kalmegh, A. paniculata of IPM blocks which ultimately resulted in low oviposition and larval population on kalmegh of IPM blocks than isolated control blocks. Amongst the IPM modules IPM Module-II (Marigold-r.c.-NSKS 5%) recorded minimum oviposition while IPM Module-IV (Marigold- T.c.-B.t.k.) and IPM Module-Ill (Marigold - T.c- HdNPW) gave effective protection to A. paniculata by preventing the larval activity of H. armigera armigera and gave considerable higher pod and seed yield. IPM Module-IV had highest (137 kg/ha) increase in pod yield, 18.76 kg/ha of seed yield and avoided loss of pod (69.11 %) and seed yield (91.25 %).IPM Module-I recorded highest I.C.B.R. (1:3.79) followed by IPM Module-III (1:3.15). Since IPM modules received no cherhical insecticide, released eggs parasitoid T. chilonis were conserved. The per cent egg parasitism due to T. chilonis was found to be 9.09 to 11.76 per cent in IPM blocks, whereas no parasitism was observed in isolated control. On the basis of above findings interspersing of marigold, two releases of Trichogramma and need based application of any one of the following may be used (1) HaNPV @ 250 LE/ha (1.5 x 10 to the power 12 POB/ha and (Z) Neem Seed Kernel Suspension 5 per cent and can be suggested for effective management of H. armigera armigera infesting A. panicidata for seed production in middle Gujarat condition.
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AGRICULTURAL ENTOMOLOGY, AGRICULTURE, MANAGEMENT