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Population dynamics and integrated management of major insect pests in okra seed crop

KrishiKosh

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Title Population dynamics and integrated management of major insect pests in okra seed crop
 
Creator Kumaranag, K.M.
 
Contributor Singh, Ram
 
Subject crops, sowing, vegetables, fruits, planting, eggs, animal developmental stages, seasons, integrated pest management, biological interaction
 
Description Field trials were carried out at Research Farm of Department of Entomology, CCS Haryana Agricultural University, Hisar for three successive kharif seasons during 2011-13 to fulfil the various objectives of the present study. The results revealed that the leafhopper, Amrasca biguttula biguttula and whitefly, Bemisia tabaci attack the crop at the early stages with their peak population observed between 32nd and 34th SW (first and third week of August) and 29th and 30th SW (third and last week of July), respectively during 2011-13. Leafhopper population had a significant positive correlation with evening relative humidity and rainfall, whereas bright sunshine hours exhibited a significant negative effect on the pest population. Whitefly population was positively correlated with maximum and minimum temperature as well as wind speed. The population of Tetranychus urticae on the crop was highest between 38th and 39th SW (third and last week of September) with its population showing significant negative correlation with minimum temperature. The highest ovioposition, larval population, per cent shoot and fruit damage by okra shoot and fruit borers, Earias spp. was noticed between 33rd and 34th SW (second and third week of August), 33rd and 36th SW (second week of August and first week of September), 35th and 36th SW, 39th SW (last week of September), respectively. Maximum and minimum temperature showed a significant negative correlation with ovipostion, larval population and fruit damage. Whereas, morning relative humidity exhibited a significant positive correlation with egg counts, larval population and per cent shoot damage. A quite low population of Helicoverpa armigera was observed on the crop from 33rd SW onwards with its peak egg and larval counts recorded between 36th and 38th SW (first and third week of September).The abundance of spiders and coccinellids was at its peak between 33rd and 34th SW (second and third week of August) during 2011-2013. Spider and coccinellids population had significant positive correlation with morning relative humidity and rainfall during 2011 and 2012. Weather parameters together contributed to fluctuation in the population of A. biguttula biguttula, B. tabaci and T. urticae to the extent of 75 to 81, 62 to 91 and 90 to 95 per cent, respectively during 2011-13. Similarly, different weather variables accounted for 64-88, 77-93, 59-93 and 81-97 per cent variation in egg counts, larval population, per cent shoot and fruit damage caused by Earias spp. across the seasons. The infestation of A. biguttula biguttula, B. tabaci and per cent shoot damage caused by Earias spp. was significantly higher on June 25th sown crop. Whereas, the incidence of T.urticae, egg and larval counts of Earias spp. and H. armigera and per cent fruit damage by Earias spp. were maximum on the July 15th sown crop. Significantly higher population of Spodoptera larvae was recorded crop sown on August 5th. Spider population was more abundant on the crop sown on June 25. However, the coccinellids population did not differed significantly on crop established on different dates. Among the IPM modules tested, module 1 containing seed treatment with imidacloprid (Gaucho 600 FS) @ 5 g a.i. /kg of seed, border cropping with sorghum, three sprays of NSKE@ 5% at 35, 55 and 80 DAS alternated with Bt (Biolep) @2g/l at 45 DAS and malathion @ 2ml/l at 60 DAS, pheromone traps for monitoring the Earias vittella, Five releases of Trichogramma chilonis @ 100000/ha and application of prempt 20 EC (fenpropathrin 5% + pyriproxyfen 15 %) @ 2l /l at 70 DAS found superior in checking the infestation of A. biguttula biguttula and B. tabaci, while all IPM modules except module 4 were equally effective in reducing the mite population. Module 2 consisting of seed treatment with thiamethoxam (Cruiser 35 FS) @ 5.7 ml/kg of seed followed by need based application of spinosad 45 SC @ 0.4ml/l, emamectin benzoate 5 SG @ 0.3 g/l and prempt 20 EC (fenpropathrin 15% + pyriproxyfen 5 %) @ 2ml/l along with collection and destruction of affected shoots effective in reducing the larval population and fruit damage by Earias spp. Lowest numbers of natural enemies were recorded in module 3, wherein sprays of conventional insecticides were alternated with NSKE 5 %. Module 2 and module 1with higher recorded seed yield, higher cost benefit ratio and safety to natural enemies were considered as most viable options for the effective management of major insect pests on okra seed crop.
 
Date 2017-06-03T03:23:57Z
2017-06-03T03:23:57Z
2015
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/5810014163
 
Language en
 
Format application/pdf
 
Publisher CCSHAU