Amongst the fifteen Chrysanthemum cultivars screened for M. sanborni infestation showed 4 less susceptible, 4 moderately susceptible, 3 susceptible and 4 highly susceptible. In case of L. trifolii, out of fifteen cultivars, 2 were found less susceptible, 8 moderately susceptible and 1 highly susceptible. The cultivar Meera showed promising results against both M. sanborni and L. trifolii recording the lowest mean population of 4.04 aphids per shoot and 2.22 live mines per plant, respectively. Studies on efficacy of different insecticides against M. sanborni indicated that 3 sprays of imidacloprid 0.01% at 15 days interval proved to be the best treatment recording 2.67 aphids per shoot. It was followed by acephate 0.075%, fipronil 0.02%, dimethoate 0.03%., chlorpyriphos 0.05%., quinalphos 0.05%., monocrotophos 0.05%., endosulfan 0.05% and cypermethrin 0.01% in decreasing order. In case of L. trifolii, chlorpyriphos 0.05% proved to be the best recorded 2.69 live mines per plant. It was followed in decreasing order by cypermethrin 0.01%., acephate 0.075%., fipronil 0.02%., quinalphos 0.05%., imidacloprid 0.01%., dimethoate 0.03%., endosulfan 0.05% and monocrotophos 0.05%.
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Date
2003
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Mahatma Phule Krishi Vidaypeeth, Rahuri
Abstract
Helicoverpa armigera Hubner is a very important polyphagous
pest ranked as "National Pest" in India. It is found to infest major crops
of the national importance. As there is no wide scale-survey on data of
losses caused by this on crops on farmers' field. Moreover, general
statements are made on the relative susceptibilities of different varieties
of crops to this pest. The per cent losses caused by this are recorded on
different pulse crops but less information is observed on feeding potential
of pea. Similarly work on use of novel (newly introduced) pesticides
against H. armigera is meagre.
Usual attempts to control the pest by the means of use of
conventional synthetic insecticides has certain limitations in bringing
about adequate and desired control. As a result, new approaches have
been tested, one of these, which have captured worldwide attention is the
use of chitin synthesis inhibitors. Another is novel broad-spectrumlepidoptericide based on oxadiazine chemistry. They have low toxicity to
mammals and their selective toxicity towards insect species; they can
assume a prominent role. Insect pathogenic viruses are major group of
microbial agent for insect pest (s) control, which would be developed as
feasible component of IPM system.
From this view point, the present investigations on feeding
potential leading to losses caused by H. armigera were carried out under
laboratory condition during 2002-2003 at Agril. Entomology Section,
College of Agriculture, Pune-5. Larva of H. armigera was allowed to
feed on 5g weighed kernels (food grains). The feeding potential on
creeping bean, chickpea, pea, pigeonpea and artificial diet were 0.68,
1.58, 1.32, 0.53 and 1.45g, respectively. The potential consumption
leading to losses to chickpea was 31.6 per cent and it was observed to be
the most preferred and susceptible host to H. armigera.
Field trial was conducted to study the bioefficacy of newer
pesticides against H. armigera infesting peatPisum sativum L. All the
pesticides during first application were significantly superior to control
with minimum per cent for damage. Novaluron 10 EC was the most
effective that registered 28.88 per cent pod damage and was at par with
indoxacarb 14.5 SC with 29.69 per cent pod damage. The quinalphos 25
EC also proved quite effective with 30.88 per cent pod damage. The rest
of treatments were in the decreasing order of their efficacy as profenofos
50 EC > endosulfan 35 EC > deltamethrin 2.8 EC > HaNPV @ 500
LE/ha > B.t.@ 625ml/ha> neem 0.03 EC.
After second application profenofos 50 EC was found effective
with 28.81 per cent pod damage and next best treatment was HaNPV @
500 LE/ha with 29.40 per cent pod damage. The performance of B.t.@
625 ml/ha and neem 0.03 EC was found to be inferior. From the pooledanalysis of means, it was revealed that treatment novaluron 10 EC was
the most effective and it recorded minimum pod damage to extent of
28.84 per cent. It was however, found statistically to be at par with the
treatment indoxacarb 14.5 SC, which recorded 29.54 per cent pod
damage. The remaining treatments except B.t.@ 625 ml/ha and neem
0.03 EC were at par with each other.
It is revealed from the above studies that, newly introduced
pesticides and HaNPV@ 500 LE/ha as microbial pesticide were
efficiently used to control damage by H. armigera.
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