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STRATEGIES FOR MANAGEMENT OF SAFFLOWER APHID Uroleucon compositae (Theobald)

KrishiKosh

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Title STRATEGIES FOR MANAGEMENT OF SAFFLOWER APHID Uroleucon compositae (Theobald)
 
Creator JEMIMAH, N
 
Contributor KOTESWARA RAO, S. R
 
Subject STRATEGIES, MANAGEMENT, SAFFLOWER, APHID, Uroleucon compositae, Theobald
 
Description Field experiments were carried out during rabi, 2011-12 at College Farm, College of
Agriculture, Rajendranagar, Hyderabad wherein effect of different dates of sowings,
weather factors and newer insecticidal molecules on incidence and management of
safflower aphid, Uroleucon compositae were studied.
Studies on effect of different dates of sowing of safflower cultivar ‘Manjeera’ on
aphid population revealed that aphid infestation was high in crop sown on second fortnight
of November (50.44 aphids/5 cm apical twig) followed by crop sown on first fortnight of
November (37.44 aphids/5 cm apical twig). Among five dates of sowing, the early sown
safflower crop evidently escaped the incidence of the aphid during the early and vulnerable
stages of the crop growth and further the mean aphid activity over a period of 16 weeks
after sowing was significantly low (7.33 aphids/5 cm apical twig) compared to other four
sowing dates (14.18-50.44 aphids/5 cm apical twig). The late sown crop succumbed to
heavy aphid infestation.
Various weather parameters affected aphid population. Safflower aphid first
appeared in the seventh week after sowing. Among abiotic factors, maximum temperature
(28.2-33.140C) found to have exerted negative significant influence on the abundance of
aphid population while minimum temperature, maximum relative humidity and sunshine
exerted a negative but non-significant correlation. Multiple regression analysis revealed all
the weather parameters collectively accounted for 83 per cent of the aphid load.
Various indices of dispersion, i.e. variance-mean ratio, dispersion parameter, David
and Moore’s index, Charlier coefficient, Index of Lexis and Llyods index of patchiness
revealed that safflower aphid followed aggregated distribution throughout the crop growth.
Six different insecticides viz., imidacloprid (0.0045%), acetamiprid (0.005%),
thiamethoxam (0.005%) profenophos (0.1%) spiromesifen (0.02%) and emamectin
benzoate (0.0005%) were tested to evaluate their relative efficacy against safflower aphid.
Two sprays were given at an interval of fifteen days. Effective reduction in population of
aphids was observed in thiamethoxam sprayed plots (97.16%) followed by acetamiprid
sprayed plots (96.43%). Aphid infestation had definite effect on yield of safflower crop.
With the increase in population of aphids, there was corresponding decrease in yield of the
crop. Maximum yield was recorded in thiamethoxam (1393 kg ha-1) sprayed plots followed
by acetamiprid (1223 kg ha-1) sprayed plots. Thus, two fortnight sprays with thiamethoxam
(97.16%) not only reduced the aphid population but also increased yield of safflower crop.
 
Date 2016-06-29T14:00:40Z
2016-06-29T14:00:40Z
2012
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/68239
 
Language en
 
Relation D9190;
 
Format application/pdf
 
Publisher ACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY