Influence of genetically modified (Bt) cotton cultivar on major insect pests
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Date
2007
Authors
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Publisher
CCSHAU
Abstract
To study the influence of genetically modified (Bt) cotton cultivars
on major insect pests, field experiments were conducted at CCS Haryana
Agricultural University, Hisar during kharif 2006. Two Bt genotypes viz.,
RCH-134 Bt and RCH-317 Bt and their corresponding non-Bt genotypes,
one hybrid (HHH-223) and one variety (H-1226) were evaluated for their
reaction to sucking pests, bollworms and natural enemies. The
experiments were laid out under three sets of conditions viz., unsprayed,
sprayed for sucking pests and sprayed for sucking and bollworm pests
control conditions. The observations were recorded by adopting standard
sampling techniques.
The results indicated that no significant difference was recorded in
sucking pest (cotton leafhopper and whitefly) populations among all
genotypes. However, the incidence of bollworm remained significantly
higher in non-Bt genotypes than their corresponding Bt genotypes.
Bollworms infestation in green fruiting bodies on Bt genotypes and
HHH-223 were below ET throughout the crop season and did not vary
significantly. However, the infestation in all genotypes ranged from
0.00-53.65 per cent under unsprayed, 0.00-52.00 per cent under sucking
pest control and 0.00-15.05 per cent under sucking and bollworm pest
control conditions. Bollworm (Earias spp.) population (larvae/plant) was
nil in Bt genotypes, while in non-B genotypes and minimum in HHH-223
under all sets of conditions.
The infestation of pink bollworm (Petinophora gosspiella) on boll and
locule basis was nil among Bt genotypes under all sets of conditions.
However, in non-Bt genotypes boll infestation ranged between 0.00-37.60,
5.10-27.60 and 2.60-12.60 per cent under unsprayed, sprayed for
sucking pests and sprayed for sucking and bollworm pests conditions,
respectively. And on locule basis it was ranged between 0.00-16.35,
1.78-13.35 and 1.19-5.78 per cent under unsprayed, sprayed for sucking
pests and sprayed for sucking and bollworm pests conditions,
respectively. Minimum incidence of pink bollworm was recorded in
HHH-223 both in boll basis and locule basis under all sets of conditions.
Bollworm infestation varied significantly in Bt and non-Bt genotypes,
being higher in non-Bt genotypes. Bollworm population (larvae/boll) was
nil among the Bt genotypes throughout the period of study.
Bollworm infestation on open boll basis in genotypes ranged from
1.05 – 33.37, 0.59 - 26.03 and 0.49 – 20.26 per cent under unsprayed,
sprayed for sucking pests and sprayed for sucking and bollworm pests
conditions, respectively, while on locule basis, the infestation ranged from
0.30 – 13.90, 0.14 – 11.60 and 0.12 – 6.37 per cent under respective
category.
Populations of natural enemies were on par in different genotypes
during period of study under different sets of experiments. Yield of seed
cotton was significantly higher in Bt genotypes than non-Bt genotypes
under all sets of conditions.
Description
Keywords
Genetically modified (Bt) cotton, Major insect-pests, Natural enemies, Population dynamics and seed cotton yield