screening elite genotypes and ipm of defoliators in groundnut

against S. litura on groundnut and also found more persistent on groundnut foliage during
kharif which was up to ten days.
According to Hegde (2001) the mycopathogen @ 2×10 8 conidia per litre sprayed
thrice against S. litura in potato at 15 days interval from 50 days after sowing proved as
effective as SlNPV and Bt and reduced the defoliators up to 32 per cent.
Influence of host plants on the response of S. litura to N. rileyi indicated that larvae
fed on groundnut were more susceptible by recording the lowest LC50 value of 5.79 × 10 6
conidia per litre followed by soybean 5.98 × 10 6 conidia per litre, potato 6.96 × 10 6 conidia per
litre and highest when feed on cotton 7.84 × 10 6 (Kulkarni and Lingappa, 2001).
According to Navi (2002) spraying of N. rileyi @ 1×10 11 conidia per hectare was most
effective in soybean and groundnut in large scale demonstration in reducing larval population
to the extent of 28 and 62 per cent in soybean, 33 and 77 per cent in groundnut after first and
second spray respectively.
Manjula et al. (2004) record the occurrence of N. rileyi on S. litura and H. armigera in
groundnut fields in Anantapur (Andhra Pradesh, India) and adjacent areas. The numbers of
cadavers and live larvae were recorded at fortnightly intervals from September 2001 until the
end of the cropping season. N. rileyi was initially observed during the first fortnight of
September, and the level of infection gradually increased to 5-10, 25-50 and 50-100% during
the second fortnight of September, first fortnight of October and second fortnight of October,
respectively. These periods were characterized by a mean maximum temperature of 31-32 ° C,
minimum temperature of 22-23 ° C, morning relative humidity (RH) of 79-84%, and evening RH
of 29-42%.
Nagaraja, (2005) reported that in groundnut crop ecosystem, different formulations of
N. rileyi and spray equipments were evaluated, the results indicated that oil based formulation
of N. rileyi with knapsack sprayer recorded significantly higher mycosis (47.43%), followed by
wettable powder and crude formulation.
A field experiment was conducted during the 2001 kharif in medium black soils in
India to study the effect of resistant (Dh-53, GPBD-4, Dh-74, Dh-86, Dh-22 (red), ICGV
86590, Dh-995, and Dh-22 (tan)) and susceptible genotypes (ICGV-92242 and Jl-24) of
groundnut on the incidence of S. litura. The reduction of the larval population due to the spray
of N. rileyi was compared with Neem Seed Kernel Extract (NSKE), insecticide (quinalphos
0.05%) spray. Insecticidal spray recorded significantly lower larval population (3.18, 2.53 and
0.82 larvae/m row at 40, 55 and 70 DAS, respectively) and leaflet damage in all the
genotypes of groundnut. Significantly higher yield (16.89 q/ha) and lowest leaflet damage was
recorded in quinalphos spray, whereas, N. rileyi and NSKE were next best in terms of yield
(14.04 and 13.83 q/ha) with lesser leaflet damage (Navi et al., 2006).
Rachappa and Lingappa (2007) conducted experiments during 2000-01 and 2001-02
at Bailhongal and during 2000-01 and 2002-03 at Dharwad, Karnataka, India, to determine
the seasonal occurrence of N. rileyi in relation to time and crop ecosystem. Fungal incidence
was more abundant on pests inhabiting soyabean and groundnut ecosystems at both
locations, e.g. Spodoptera litura, T. orichalcea and H. armigera. These crops, aside from
being suitable for host insect build-up and providing congenial microclimate with their host,
predisposed the insect larvae to higher and quicker infection.
2.2.5 Integrated pest management for Spodoptera litura (F.)
Mahesh (1996) reported that integration of raising tolerant varieties, raising trap crops
like castor and sunflower around the fields and within the field respectively. These trap crops
will act as perches for predatory birds and laying of eggs on the broader leaves as per the
performance of the pest. Installation of pheromone traps to predict oviposition, application of
neem seed kernel extract during early stages of the crop and spraying of NPV @ 250 LE per
hectare will be a good management strategy for S. litura in groundnut.