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EVALUATION OF NEWER INSECTICIDES AGAINST SUCKING PESTS IN BLACKGRAM

KrishiKosh

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Title EVALUATION OF NEWER INSECTICIDES AGAINST SUCKING PESTS IN BLACKGRAM
 
Creator SIREESHA, K
 
Contributor SESHA MAHALAKSHMI, M
 
Subject sowing, insecticides, cotton, seed treatment, diseases, planting, crops, land resources, vegetables, yields
 
Description Studies on “Evaluation of newer insecticides against sucking pests in
blackgram” were undertaken during Rabi 2011-2012 at Regional Agricultural
Research Station, Lam, Guntur.
The incidence of sucking pests i.e both thrips and whiteflies was observed
through out the crop growth period in blackgram. Initially, the incidence of thrips
was observed from 10 days after sowing while it was from 15 DAS onwards for
whiteflies. The peak incidence of thrips was observed during 5th standard week
(64 DAS) with a population of 8.26 thrips/trifoliate leaf/plant. All the weather
parameters together accounted for 83.23 per cent significant variation in thrips
population (R2=0.8323) and maximum and minimum temperatures, morning and
evening relative humidities also could independently affect changes in thrips
population.
The activity of whiteflies was observed from 50th standard week till the
end of the crop season. The peak incidence of whitefly population was observed
during 5th standard week (64 DAS) with a population of 1.4 nymphs/trifoliate
leaf/plant. The multiple linear regression analysis revealed that all the weather
factors together were responsible for 53.93 per cent (R2 value) of total variation
in whitefly population though it was non-significant.
Among the natural enemy complex observed in the blackgram ecosystem,
coccinellid beetles and spiders were the dominant predators. The population of
natural enemies was observed throughout the crop growth period with a peak
abundance during 5th standard week coinciding with peak activity of sucking
pests. All the weather parameters together exerted a very high and significant
influence of 87.33 per cent on the population of natural enemies.
Seed treatment with neonicotinoid insecticides was found to protect the
crop from sucking pests upto 25 days after sowing only even at the higher
dosage. Irrespective of the insecticides tested, higher doses of the insecticides (10
ml/kg) seed were found effective in controlling the thrips and whiteflies in
blackgram. Among all the treatments, imidacloprid 200 SL at 10 ml/kg seed was
found to be effective against thrips followed by thiamethoxam 70 WS (10 g/kg
seed). While, thiamethoxam 70 WS at 10 g/kg was proved better against
whiteflies followed by imidacloprid 200 SL at 10 ml/kg.
Phytotoxicity was not observed even at higher doses since there was no
reduction in per cent germination and initial plant stand with any of the
insecticides. Besides, some phytotonic effect of seed treatment was observed,
since there was significant increase in plant height in all the insecticidal
treatments compared to control at 30 days after sowing. The disease incidence of
YMV recorded at 30 days and 60 days after sowing revealed that lowest YMV
incidence was observed in the seed treated plots with higher doses (10 g or ml/kg
seed) of thiamethoxam, imidacloprid and thiacloprid. The seed yield of
blackgram was high from thiamethoxam treated plot at 10 g/kg seed (1088 kg/ha)
followed by imidacloprid at 10 ml/kg seed (1074 kg/ha).
Among all the insecticides evaluated as foliar sprays, spinosad 45 SC
0.0135 per cent was found significantly superior in reducing the thrips population
followed by fipronil 5 SC 0.005 per cent. Whereas, spiromesifen 240 SC 0.096
per cent was found highly effective against whiteflies followed by buprofezin 10
EC 0.01 per cent, with high per cent reduction in population over control. Among
the neonicotiniods tested, imidacloprid 200 SL 0.06 per cent and thiamethoxam
25 WG 0.005 per cent were found promising against thrips, while acetamiprid 20
SP 0.004 per cent and thiacloprid 21.7 SC 0.027 per cent proved better against
whiteflies with moderate efficacy. The seed yield of blackgram was highest from
spiromesifen 240 SC 0.096 per cent (1188 kg/ha) followed by buprofezin 10 EC
0.01 per cent (1146 kg/ha). However all the treatments were found significantly
superior over the untreated control both in terms of pests suppression and seed
yield in blackgram.
 
Date 2016-06-21T13:57:26Z
2016-06-21T13:57:26Z
2012
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/67602
 
Language en
 
Relation D9390;
 
Format application/pdf
 
Publisher ACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY