Occurrence of Pest Complex on Postrainy Groundnut (Arachis hypogaea L.) and their Management with Bio-rational Insecticides
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Date
2006
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ACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY, RAJENDRANAGAR, HYDERABAD
Abstract
Studies on the “Occurrence of Pest Complex on Post-rainy Groundnut
(Arachis hypogaea L.) and their Management with Bio-rational Insecticides”
were undertaken during rabi, 2005-06 at Agricultural College Farm, Bapatla.
The occurrence of pest complex on groundnut was recorded at weekly
intervals from a total of 50 plants from five different locations (ten randomly
selected and tagged plants per location) throughout the cropping period in the
unprotected bulk plot. The data with regard to the seasonal incidence indicated
that January and February months were favourable for the multiplication of
tobacco caterpillar, Spodoptera litura (Fab.), groundnut leafminer, Aproaerema
modicella (Dev.), leafhopper, Empoasca kerri (Pruthi) and groundnut thrips,
Thrips palmi (Karny). The peak incidence of S. litura was recorded during the
last week of January while, A. modicella during the second week of February.
Regarding the sucking pests, the peak incidence of T. palmi was recorded
during the third week of January while, E. kerri during the fourth week of
January.
In the management trial, the efficacy of the bio-rational insecticides and
their combinations against S. litura, A. modicella, E. kerri and T. palmi was
evaluated in a randomized block design with three replications.
The results indicated that the individual treatment, emamectin benzoate
0.0025% was the most effective followed by indoxacarb 0.0145%, indoxacarb
0.00725% + novaluron 0.005% and indoxacarb 0.00725% + B.t.k. 0.1% in
reducing the larval population of S. litura and A. modicella and also infestation
by A. modicella. Among all the treatments, azadirachtin 0.3% was found to be
the least effective against S. litura whereas SlNPV 250 LE ha-1 was the least
effective against A. modicella.
In case of sucking pests, E. kerri and T. palmi, the evaluation of
different treatments revealed that the individual treatment, endosulfan 0.07%
was the most effective in reducing the population of E. kerri and T. palmi
followed by azadirachtin 0.3%. The treatments, B.t.k. 0.2%, N. rileyi 1.2x108
spores ml-1, SlNPV 125 LE ha-1 + B.t.k. 0.1% and SlNPV 250 LE ha-1 were the
least effective against sucking pests, E. kerri and T. palmi.
The treatment, emamectin benzoate 0.0025% recorded the highest pod
yield followed by indoxacarb 0.0145%, indoxacarb 0.00725% + novaluron
0.005% and indoxacarb 0.00725% + B.t.k. 0.1% whereas the treatments, N.
rileyi 1.2x108 spores ml-1 and SlNPV 250 LE ha-1 recorded the lowest pod
yields.