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Population dynamics of different insect-pests and arthropods natural enemies on various Bt cotton gene events

KrishiKosh

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Title Population dynamics of different insect-pests and arthropods natural enemies on various Bt cotton gene events
 
Creator Roomi Devi
 
Contributor Dahiya, K.K.
 
Subject Biological phenomena, Crops, Yields, Productivity, Participation, Land resources, Economics, Byproducts, Livestock, Area
 
Description The present study was carried out at the Research Farm of Cotton Section, Department of
Genetics and Plant Breeding, CCS Haryana Agricultural University, Hisar during kharif 2014. Seven
genotypes comprising five Bt hybrids (BIOSEED-6588, NECH-6, JK-1947, SP-7007, RCH-134), one
non-Bt hybrid (HHH-223) and one non-Bt variety (H-1236) were evaluated for their reaction to sucking
pests, natural enemies and bollworms under unsprayed condition. The observations on sucking pests
viz., whitefly, thrips, leafhopper, natural enemies and bollworms damage were recorded at weekly
intervals. Bollworms damage were also recorded at 90, 120, 140 DAS and finally at harvest. At harvest
damage was assessed on boll as well as on locule basis. Results revealed that pests remained active
throughout the crop season. On the basis of weekly mean values whitefly and leafhopper attained two
peaks; one on 34
th
, 39
th
second on 28
th
and 33
rd
SMW with 25.27 and 28.32 adults/leaf and 2.79 and
3.29 nymphs/leaf, respectively. However, thrips attained only one peak on 33
rd
SMW with 11.29
thrips/leaf. Maximum population of whitefly and thrips was recorded in Bt genotype RCH-134 and that
of leafhopper in NECH-6 while minimum in HHH-223, Bt NECH-6, H-1236, respectively. Bt
genotypes attracted more population of whitefly as compare to non-Bt genotypes. Whitefly and
leafhopper were positively correlated with RH, negatively with temperature while thrips showed
positive correlation with RH and temperature. Natural enemies (Chrysoperla, Coccinellids and Spiders)
were also active throughout the crop season. Chrysoperla, Coccinellids and Spiders attained two peaks
on 29
th
, 38
th
, 27
th
, 38
th
, 35
th
and 40
th
, SMW respectively with number of 1.56, 1.53 Chrysoperla
eggs/plant, 2.41, 2.17 adults/plant and 2.64, 2.28 adults/plant, respectively. Maximum population of
Chrysoperla, Coccinellids and Spiders observed in RCH-134, HHH-223 and JK-1947 while minimum
in NECH-6, SP-7007 and H-1236, respectively. Parasitoids (Encarsia spp.) were also found to be
associated with B. tabaci. Parasitoids attained two peaks throughout the crop season on 35
th
and 38
th
SMW with 38.28 and 42.66 per cent parasitization respectively. Highest parasitization was recorded in
NECH-6 (31.32%) and lowest in H-1236 (20.19%). Minimum damage in bolls (1.05%), squares and
flowers (1.45%) and shed material (4.09%) by bollworms was observed in Bt genotype BIOSEED-6588 while it was highest in non Bt variety H-1236 with 15.20, 15.18 and 20.97 per cent, respectively.
Similarly, damage at open boll and locule also observed maximum in H-1236 (28.68%) and (6.70%)
respectively, however, minimum damage was recorded in BIOSEED-6588 (1.27%) and (0.40%),
respectively. Bt genotypes were significantly superior than non-Bt genotypes in yield and managing
bollworms.
 
Date 2016-10-21T11:18:22Z
2016-10-21T11:18:22Z
2015
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/81202
 
Language en
 
Format application/pdf
 
Publisher CCSHAU