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Bio-efficacy of safer insecticides against fruit and shoot borer (Earias vittella Fab.) and spider mite (Tetranychus urticae Koch) of okra

KrishiKosh

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Title Bio-efficacy of safer insecticides against fruit and shoot borer (Earias vittella Fab.) and spider mite (Tetranychus urticae Koch) of okra
 
Creator Behera, Anupama
 
Contributor Sahoo, B.K.
 
Subject Bio-efficacy of safer insecticides ag fruit and shoot borer, spider mite, okra
 
Description Field experiment on the study of important pests like shoot and fruit borer, Earias vittella Fab. and mites, Tetranychus urticae Koch infesting okra, Abelmoschus esculentus (L) Moench, and their damage potential at different growth stages, seasonal abundance in relation to abiotic factors and evaluation of safer pesticides were conducted with eight treatments at the Central Research Station, Orissa University of Agriculture and Technology, Bhubaneswar, Odisha during Rabi 2014-2015 as foliar spray on okra c.v, Arka Anamica.
The result revealed that incidence of E. vittella Fab. commenced on 47th SW of 2014 (vegetative Stage) with 2.9 larvae/plant and then declining from 1st SW of 2015 (Fruiting Stage) due to the effect of rainfall. Whereas, T. urticae Koch first appeared in 46th SW (vegetative stage) and continued up to 52nd SW (beginning of fruiting stage) with a population range of 5.2 to 8.9 / cm2 of leaf.
The population and incidence of E. vittella Fab.and T. urticae Koch were adversely affected with the abiotic factors like temperature (r = -0.847* and r = -0.502 respectively), relative humidity(r = -0.497 and r = -0.428 respectively) and rainfall (r = -0.056 and r = -0.229* respectively) during the cropping period. The relative abundance of borer was found to be 16.6 (6.0/plant), 10.5 (3.8/plant), 8.3 (3.0/plant), 64.5 percent (23.3/plant) and for mite 27.5 (18.5/cm2 of leaf), 13.2 (8.9/cm2 of leaf), 8.9 (6.0/cm2 of leaf) and 50.3 percent (33.8/cm2 of leaf) at different stages of the crop i.e, vegetative, budding, flowering and fruiting stage respectively.
Bio-efficacy evaluation of pesticides against the fruit and shoot borer, E. vittella Fab and spider mite, T. urticae Koch concluded that the two treatments, Spinosad 45 SC @0.12 ml/l +Bacillus thuringiensis (Bt) @ 1ml/l + Abamectin @ 0.5ml/l and Spinosad 45SC @0.12 ml/l + Abamectin @ 0.5ml/l recorded lowest larval population of 2.0 per plant with 55.1% reduction over untreated check (UC) as compared to other treatments. The shoot and fruit damage were also low (1.8 - 1.9% shoot damage, and 5.9 - 8.4% and 4.6 - 9.1% fruit damage on number and weight basis respectively) by these two treatments. The higher yield of 74.1 and 70.6 q/ha with cost: benefit ratio of 1:2.82 and 1:2.48 were also obtained by these two treatments which were statistically at par with each other. The rest treatments recorded the yield of 60.5 - 68.7 q/ha registering the avoidable yield loss of 15.7 - 25.0% and 18.6 - 33.3% increase in yield over UC with a cost benefit ratio of 1:0.78 - 1:2.07. Further the treatment, Abamectin @ 1ml/l was quite effective in controlling mite with 28.2% reduction of population over UC giving a yield of 66.5 q/ha and cost: benefit ratio of 1:1.92.
Therefore, the combination of two safer pesticides like Spinosad 45 SC @0.12 ml/l + Abamectin @ 0.5ml/l may be recommended as an alternative for the management of okra shoot and fruit borer and mites, whose efficacy was at par with the combination of three safer pesticides in enhancing the fruit yield.
 
Date 2017-01-04T15:14:10Z
2017-01-04T15:14:10Z
2015
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/94503
 
Language en
 
Format application/pdf