screening elite genotypes and ipm of defoliators in groundnut

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ecome an integral part of the process of identifying and studying pest resistance in groundnut (Prasad et al., 2000). Groundnut genotypes such as ICGV- 86699 Tan, Mutant III, GPBD-6, GPBD-5, ICGV- 86699 Red, GPBD-4 and susceptible check (JL-24), were utilized for rearing S. litura. The effect of these genotypes on larval, pre pupal, pupal, pre oviposition, oviposition and post oviposition period, larval weight, larval mortality, per cent pupal survival ,pupal weight ,adult longevity, per cent adult emergence and fecundity of S. litura was ascertained on each of the elite genotypes. The present study demonstrated existence of substantial amount of variability in host, affecting these biological parameters. 5.1.1.1 Larval period The length of larval duration was affected in larvae fed on foliage of test genotypes (Table 2) and there by reduces biotic potential of the pest. The genotypes Mutant III and ICGV- 86699 Tan recorded longer larval duration in each instars compare to other genotypes. While in susceptible genotypes viz., GPBD-4 and JL-24 recorded shorter larval duration (Fig. 3). The present study corroborate with the findings of Patil et al. (1995) where in S. litura had stretched larval duration on ICGV-87165, ICGV- 86350 and ICGV- 87264. Bioassay carried out with the larvae to understand the mechanism of resistance by Wightman and Ranga Rao (1994) revealed no antibiosis effect on II and IV instar larvae when fed to matured leaves of ICGV- 86031. Spodoptera frugiperda (S.) fed with resistant florunner took more days to develop compared to larvae fed with curly leaf (Todd et al., 1991). It has also been showed that longer larval duration on resistant genotypes, NC Ac -2243 (Xi Jia LI , 1987) was longer. 5.1.1.2 Larval weight and larval mortality The genotypes Mutant III and ICGV- 86699 Tan recorded significantly low larval weight and high percentage of mortality at all the stages compared to susceptible genotypes GPBD-4 and JL-24 (Table 3 and Fig. 2). The larval per cent mortality was high on resistant genotypes in early stages compare to susceptible genotypes indicating the vulnerability of neonate larvae to the existing resistant factor. According to Stevenson et al. (1993) in pest control strategies, neonate larvae should be a primary target in host plant resistance because plant damage can be minimized if pest is eliminated as early in the life cycle as possible. The higher larval mortality of S.litura on resistant groundnut genotypes like ICGV-86031, wild tetraploid Arachis manticola was also reported by many workers (Kulkarni, 1989; Dwivedi et al., 1993; Wightman and Ranga Rao, 1994; Patil et al., 1995; Prasad and Gowda, 2006). Mortality at early stages has also been observed in Heliothis zea when reared on maize plant. The development of first stadium larvae of H. zea was retarded by the presence of chlorogenic acid and rutin in artificial diet (Isman and Duffey, 1982). Present findings corroborates with the findings of Prasad and Gowda (2006) where in the larval weight was significantly low from larvae fed on the foliage of resistant genotypes NC Ac 343, Mutant 28-2 and R 9227. Singh and Sachan (1992) identified ICGV-86030, ICGV- 86031 and NC Ac 343 as resistant to S. litura based on survival, weight gain and larval duration. The differential response of the genotypes on larval parameters indicates the possibility of antibiosis mechanisms of resistance operating in them. The effect of resistant genotypes on larval mortality in early stage, gain in larval weight and growth of the larvae could obviously be due to chemical factors, i.e. antibiosis as elucidated by Painter (1951). The chemicals viz., querecitin glycosiden, chlorogenic acid and rutin have been reported to be the cause for resistance in wild Arachis species (Stevenson, 1993) and could be the cause for antibiosis. However, physical resistance (leaf thickness) may be also important as panitrometric studies showed that leaves of resistant wild Arachis species required a greater biting effort than did the leaves of susceptible TMV-2 and more susceptible of Arachis. 5.1.1.3 Pupal development and moth emergence The resistant effect of Mutant III and ICGV- 86699 Tan were also observed on pupal duration, pupal weight, per cent pupal survival and moth emergence (Table 5 and 4). Similar
Larval period and Total developmental period (egg-adult) 60 50 40 30 20 10 0 Larval period Total developmental period (egg-adult) Fecundity (eggs/female) GPBD-5 ICGV-86699 Red ICGV-86699 Tan GPBD-6 Mutant-III GPBD-4 JL-24 (Susceptible check) Genotypes Fig. 2: In vitro biology of Spodoptera litura on elite groundnut genotypes 700 600 500 400 300 200 100 0 Fecundity (eggs / female)
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SCREENING ELITE GENOTYPES AND IPM O
Page 3 and 4: CONTENTS Sl. No. Chapter Particular
Page 5 and 6: Figure No. LIST OF FIGURES Title 1.
Page 7 and 8: In some parts of the northern Karna
Page 9 and 10: mutants were systematically screene
Page 11 and 12: observed on Dwarf Mutant, the lowes
Page 13 and 14: Singh and Sachan (1991) recorded se
Page 15 and 16: Thontadarya and Nangia (1983) repor
Page 17 and 18: Monitoring with pheromone traps to
Page 19 and 20: 1. JL-24 (Susceptible check) 2. ICG
Page 21 and 22: Observations were recorded daily on
Page 23 and 24: Table 1: Performance of elite groun
Page 25 and 26: Third instar duration was significa
Page 27 and 28: Table 3: Gain in larval weight and
Page 29 and 30: Table 4: Biological parameters of S
Page 31 and 32: Table 5: In vitro biology of Spodop
Page 33 and 34: sunflower and N. rileyi, foxtail mi
Page 35 and 36: Table 7: Leaf hoppers population in
Page 37 and 38: Table 8: Thysanoplusia orichalcea p
Page 39 and 40: Table 10: Spilarctia obliqua popula
Page 41 and 42: 4.2.4.2 50 days after sowing The de
Page 43 and 44: Table 13: The management of Spodopt
Page 45 and 46: The early instar larvae scraped the
Page 47 and 48: Module I Table 16: Natural enemy po
Page 49 and 50: Table 18: Natural enemy population
Page 51 and 52: Table 19: Economics of IPM modules
Page 53: Per cent defoliation 50 45 40 35 30
Page 57 and 58: Larval Larval weight weight (g) (g)
Page 59 and 60: 5.2.3 Defoliator population in thre
Page 61 and 62: Pest population 1600 1400 1200 1000
Page 63 and 64: Gross returns and Net returns (Rs./
Page 65 and 66: REFERENCES Agasimani, C. A., Ravish
Page 67 and 68: Kennedy, F. J. S., Rajamanickam. K.
Page 69 and 70: Prasad, M. N. R. and Gowda, M. V. C
Page 71 and 72: Tiwari, S. N., Rathore, Y. S. and B
Page 73: SCREENING ELITE GENOTYPES AND IPM O
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screening elite genotypes and ipm of defoliators in groundnut

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