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Bioecology and management of mealybug, phenacoccus solenopsis Tinsley (Hemiptra: Pseudococcidae) on Bt cotton

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Title Bioecology and management of mealybug, phenacoccus solenopsis Tinsley (Hemiptra: Pseudococcidae) on Bt cotton
 
Creator Shivanand.G.Hanchinal
 
Contributor B.V.Patil
 
Subject Agricultural Entamology
 
Description Investigations were carried out on survey, seasonal fluctuation of mealybug,
Phenacoccus solenopsis Tinsley and its natural enemies, crop loss assessment, estimation of
EIL, biology of mealybug, biology of the predator Cryptolaemus montrouzieri Muls. and
efficacy of insecticides including biological agents against mealybugs were undertaken
during 2008-09 and 2009-10 at MARS, Raichur and Department of Entomology, College of
Agriculture, Dharwad.
Mealybug incidence was moderate to severe in Raichur, Bellary and Gulbarga
districts while its incidence was low in Dharwad, Haveri and Belguam districts of North
Karnataka on Bt cotton. The peak activity of the parasitoids was observed mainly from
January to March in both the years. Mean per cent parasitoid emergence from mealybugs
collected at various places was highest in TBP and UKP areas as compared to other districts
in both the years. There were more than 15 alternate host plants of P. solenopsis belonging to
eight families found across the cotton growing districts of North Karnataka. Among them,
Abutilon indicum L. (Malvaceae) and Parthenium hysterophorus L. (Asteraceae) were the
major weed hosts.
Steep increase in the mealybug population was observed from January and reached
peak in March in both the years of study. Initially parasitoid population was low and peak
activity started during first week of January which gradually increased up to 34.62 per cent
and 34.64 per cent during the last week of March 2008-09 and 2009-10 seasons, respectively.
Among different parasitoids, Aenasius bambawalei Hayat was the dominant species. Total
life cycle of P. solenopsis female and male was 38.47 and 20.33 days, respectively. The total
life cycle of Cryptolaemus montrouzieri was 28.82 and 24.71 days when reared on the
mealybug nymphs and adult female, respectively.
Crop loss estimation due to mealybug damage indicated that cotton plants did not
survive at all the damage levels at 60 days after sowing in both the years. Cotton
yield was severely affected due to different levels of mealybug damage at 90 days after
sowing. Estimation of EIL due to mealybug damage on Bt cotton under irrigated ecosystem
resulted in 20, 27, 44 and 51 mealybugs per plant at 60, 90, 120 and 150 days after sowing,
respectively. Profenophos 50 EC @ 2000 ml/ha and buprofezin 25 SC @ 1500 ml/ha were
effective in reducing the mealybug population on cotton. These two treatments recorded
significantly maximum seed cotton yield with higher net returns in both the seasons of study.
 
Date 2016-07-23T11:24:52Z
2016-07-23T11:24:52Z
2010
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/69511
 
Format application/pdf
 
Publisher UAS Dharwad