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Subject: Entomology × Author: Gaurav Singh × End date: 2018 × Start date: 2016 × Type: Thesis × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Population dynamics and eco-friendly management of maize stem borer, chilo partellus (Swinhoe) on maize
    (CCSHAU, 2018) Gaurav Singh; Maha Singh
    Present investigations on “Population dynamics and eco-friendly management against maize stem borer, Chilo partellus (Swinhoe)” were conducted during Kharif, 2017 at laboratory and research area of CCS Haryana Agricultural University, Regional Research Station, Uchani, Karnal. Results of weekly observations on pest population showed that eggs of C. partellus were present in field during 27th to 31st standard meteorological week (SMW) whereas larval population was active during 28th to 35th SMW. Peak larval and pupal population was recorded during 31st (3.8 larvae /plant) and 35th SMW (1.5 pupae/ plant), respectively. Per cent cumulative (47.5%) and fresh infestations (11.5%) were recorded to be maximum during 34th and 28th SMW whereas per cent cumulative (18.8%) and fresh dead heart (7.1%) showed a peak during 33rd and 29th SMW, respectively. Eggs of C. partellus showed a highly significant positive correlation with minimum temperature (r=0.775) and significant negative correlation with morning relative humidity (r=-0.593), while larval population showed significant positive correlation with minimum temperature (r=0.594) and evening relative humidity (r=0.635). Multiple linear regression analysis showed that all weather parameters contributed towards fluctuation in C. partellus egg masses, larvae, pupae, cumulative per cent plant infestation, fresh per cent plant infestation, cumulative dead heart and fresh dead heart to the extent of 86, 68, 57, 74, 93, 69 and 88 per cent, respectively. Population of coccinellids, spiders, egg parasitization and larval parasitization were maximum during 39th (1.84/plant), 35th (0.62 spiders/ plant), 28th (6.53 %) and 33rd SMW (31.64 %), respectively. Screening of sixteen maize genotypes revealed that four genotype viz., CM 500, HQPM 4, HQPM 7 and HM 9 were found resistant against C. partellus with LIR ranging from 0-3. Morphological characters such as leaf length, leaf trichomes, weight of 100 grains, internode distance, and stem diameter exhibited a significant negative correlation with LIR score. Results on efficacy of Trichogramma chilonis revealed that minimum LIR, plant infestation and dead hearts was recorded in treatment with two releases of T. chilonis parasitized eggs @ 1,25,000/ha at 7 and 14 DAG which was at par with two releases of T. chilonis parasitized eggs @ 1,00,000/ha at 7 and 14 DAG. The most economically remunerative treatment with the highest recorded B:C ratio (1.43) was treatment with one spray of dimethoate 30 EC @ 660 ml/ha at 7 DAG whereas highest incremental cost:benefit ratio (1:32.48) was recorded in treatment with two releases of T. chilonis parasitized eggs @ 1,25,000/ha at 7 and 14 DAG. Results on evaluation of cowpea as intercrop revealed that minimum LIR (2.48) was recorded in treatment with intercropping of maize with cowpea (1:1) whereas minimum plant infestation (8.1%) and dead hearts (4.5%) was recorded in treatment with sole maize+ spray of dimethoate 30EC @ 660 ml/ha at 7-10 DAG. Highest B:C ratio (1.63) was recorded in treatment with maize + cowpea (1:1) with maize yield 4227 Kg ha-1 and cowpea yield, 596 Kg ha-1.