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Bio Ecology and Management of Tobacco caterpillar, Spodoptera litura (F.) and Ragi cutworm, Spodoptera exigua (Hb.) infesting rabi, onion (Allium cepa)

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Title Bio Ecology and Management of Tobacco caterpillar, Spodoptera litura (F.) and Ragi cutworm, Spodoptera exigua (Hb.) infesting rabi, onion (Allium cepa)
 
Creator SAILAJA RANI ZAMPANI
 
Contributor SUBBA RAO, D.V
 
Subject Bio, Ecology, Management, Tobacco, caterpillar, Spodoptera, litura, Ragi, cutworm, Spodoptera, exigua, Infesting, rabi, onion
 
Description Investigations on the bioecology and management of tobacco caterpillar,
Spodoptera litura (F.) and ragi cutworm, Spodoptera exigua (Hb) were conducted
on onion crop in farmers fields of Yarrabalem village of Mangalagiri mandal,
Guntur district during rabi, 2003-04.
Studies on the incidence of the pests indicated that both the cutworms
infested the onion crop during the same period more or less with a same level of
larval population. The infestation of the pests was observed for a period of ten
weeks commencing from 12th November to 21st January. Maximum larval
population of S. litura and S. exigua was recorded from 24th to 31st December and
1st to 7th January respectively with a maximum collective foliar damage from 24th to
31st December. Larval density of both the pests on the onion crop was significantly
and negatively correlated with maximum air temperature. Multiple linear
regression analysis showed that for every 10C decrease in maximum air
temperature, there was an increase of 5.25 and 5.75 larvae per ten plants of S. litura
and S. exigua respectively.
Coccinellid beetle, Verania vincta G. was recorded as a major predator in
onion crop ecosystem with a maximum population from 24th to 31st December
synchronizing with the peak occurrence of the pest population. Maximum air
temperature was found significantly and negatively correlated with predatory
coccinellid population.
Screening of eco-friendly and safer insecticides revealed that spinosad 0.015
per cent spray was effective against target pests and realized higher bulb yield with
a corresponding higher net monetary benefit and cost benefit ratio. Indoxacarb
0.0145 per cent spray was the next best treatment with higher initial toxicity against
the pests which may be considered in the situations of severe infestation of the pest
during initial stages of the crop growth (within one month after planting) where the
pest has to be controlled in shorter time to avoid the possible replanting of onion
crop.
Treatments viz., lambdacyhalothrin 0.01 per cent, chlorpyriphos 0.05 per
cent, B.t. 0.5 kg ha-1 + NPV 150 LE ha-1, B.t. 1 kg ha-1, NPV 300 LE ha-1, novaluron
0.01 per cent and lufenuron 0.01 per cent offered intermediate efficacy while the
entomophagous fungi, Beauveria bassiana 1x108 spores/ml, Nomuraea rileyi 1x108
spores/ml and plant origin insecticide, neemoil 0.5 per cent were found less
effective against the target pests with a proportionate bulb yield, net monetary
benefit and cost benefit ratio.
 
Date 2016-08-20T10:27:41Z
2016-08-20T10:27:41Z
2004
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/73106
 
Language en
 
Relation D7633;
 
Format application/pdf
 
Publisher ACHARYA N. G. RANGA AGRICULTURAL UNIVERSITY, RAJENDRANAGAR, HYDERABAD