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Assessment of Partitioned Growth Stage Yield Losses Due to insect Pests of Cotton

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Title Assessment of Partitioned Growth Stage Yield Losses Due to insect Pests of Cotton
 
Creator Patel, Chamanlal Jethabhai
 
Contributor Purohit, M.S.
 
Subject null
 
Description Investigations were carried out during kharif 2002 and Kharif
2003 on "Partitioned growth stage yield losses due to insect pest of cotton"
at Main Cotton Research Station, Navsari Agricultural University, Athwa
Farm, Surat. Efficacy of insect growth regulators against Helicoverpa larvae
and effect of BI cotton on growth parameters of Helicoverpa larvae was also
studied under laboratory condition. Study on determination of critical stages
for protection against insect pests in cotton revealed ER +PR stages as
critical for protection against aphids, jassids and thrips whereas PR+LR
stages for whitefly. For spotted bollworm and Helicoverpa infestation to
fruiting bodies (squares + green bolls) ER+PR stages ascertained as critical
stages. However, significant reduction in open boll damage by bollworm
complex was achieved in full protection (FP) only. Incidence of spotted
bollworm and Helicoverpa in open bolls and locules was higher in first
picking compared to second picking. Reverse was the trend for pink
bollwOlIII incidence in open bolls and locules. Full protection treatment
recorded significantly higher seed cotton yield (2478 kg/hal. It was followed
by ER+PR+LR (2279 kg/hal, ER+PR(2088 kg/hal, V+ER+PR (2054 kg/hal,
ER+LR(2045 kg/hal, V+ER+LR (2033 kg/hal, V+PR+LR( 1737 kg/hal and
I'R+LR (1682 kg/hal· The yield increase in full protection treatment over
control was 91.94 per cent. In rest of treatments the increase in yield over
control ranged from 30.29 to 76.63 per cent. When V, ER, PR, and LR stage
received no protection the reduction in yield was 199, 741, 445 and 424 kg
seed cotton fha, respectively. The corresponding figure in terms of per cent
yield reduction over protection provided in these stages were 8.03, 29.90,
17.95 and 17.11, respectively. The maximum avoidable loss in seed cotton
yield (47.90 %) was in the treatment of full protection (FP) followed by full
protection in reproductive period (ER+PR+LR) (43.35 %). Whereas,
treatments not recei·ved protection in ER stage showed minimum avoidable
loss (23.25 to 25.68 %) indicating the significance of ER stage protection.
Highest cost benefit ratio (I: 3.70) was obtained in ER+LR stage protection.
Studies on efficacy of insect growth regulators (lGR) on
Helicoverpa larvae revealed that both the lGR, novaluron (Rimon) and
flufenoxuron (Cascade) was found effective against Helicoverpa larvae.
Early instar larva was found more susceptible than later instar. Post
treatment effect of IGR prolonged larval and pupal period, reduction in
larval and pupal weight, low adult emergence without much impact on
longevity.
Effect of BI cotton on Helicoverpa larvae revealed profound
effect of BI cotton leaves and squares when fed to the larvae, leading to 90
% mortality in 2nd and 4th instar and 100 per cent mortality in I st and 3,d
instar. BI cotton fed survived larva showed prolonged larval period,
reduction in larval length, larval weight and pupal weight, but negligible
effect on pupal period over larva fed on non-Bt cotton. Debilitating effect
was more on BI squares compared to BI leaves.
 
Date 2018-06-12T05:55:48Z
2018-06-12T05:55:48Z
2006-11
 
Type Thesis
 
Identifier CHAMANLAL JETHABHAI PATEL_37289
http://krishikosh.egranth.ac.in/handle/1/5810051209
 
Language en
 
Format application/pdf
 
Publisher Agricultural Entomology Department, N. M. College of Agriculture, Gujarat Agricultural University