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Subject: Entomology × Author: Raj Kumar × End date: 2023 × Start date: 2022 × Type: Thesis ×
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    ThesisItemOpen Access
    Studies on biorational management of spotted stem borer, Chilo partellus in fodder sorghum
    (CCSHAU, Hisar, 2023-04-04) Raj Kumar; Dalip Kumar
    The present investigations were carried out on “Studies on biorational management of spotted stem borer, Chilo partellus in fodder sorghum” during Kharif, 2021 at CCS HAU, Hisar. Impact of date of sowing on incidence of sorghum stem borer and shoot fly in sorghum crop studied. Number of eggs laid by sorghum shoot fly at 7 and 14 days after emergence (DAE) was lowest in the crop sown on 21st July (0.67 and 1.33, respectively) and was highest in the crop sown on 11th August i.e., 3.00 and 4.00, respectively. Sorghum crop sown on 21st July showed significantly lowest per cent of deadheart incidence (12.33 and 15.39) while, crop sown on 11th August showed higher per cent of deadheart incidence i.e., 25.52 and 29.78 at 21 and 28 DAE, respectively. Deadheart per cent by sorghum stem borer was recorded lower (16.42) in crop sown on 21st July as compare to crop sown on 11th August (27.79) at 45 DAE. Evaluation of forty sorghum genotypes for their resistance against sorghum shoot fly was done on the basis of number of eggs, deadheart per cent, plant vigour, glossiness of leaves and shape of plant canopy and for sorghum stem borer was done on the basis of number of pin holes, leaf feeding at 7, 21 and 42 DAE, number of larvae per plant, stem tunneling, deadheart (%) formation at 45 DAE, plant height, number of total stalks and damaged stalks, plant vigour, glossiness of leaves and plant canopy. Deadheart (%) formation caused by shoot fly varied from 6.23 to 23.94 per cent at 21 DAE and from 11.42 to 43.48 (%) at 28 DAE in different sorghum genotypes. Resistant genotypes viz., IS 2312 and IS 2205 recorded least deadheart (%) while, susceptible genotypes, Swarna and DJ 6514recorded highest deadheart percentage. Deadheart formation (%) due to sorghum stem borer was recorded minimum in resistant checks IS 2312 (11.00%) and maximum deadheart in susceptible check, Swarna (45.38%) at 45 DAE. Forty sorghum genotypes were categorised into different classes on the basis of deadheart per cent formation on a 1-9 scale at 45 DAE and all the screened sorghum genotypes fallen within a range of 2-5. Seven sorghum genotypes were assigned a scale rating of 2 having deadheart (%) ranges from 11 to 20. 12 genotypes received a scale rating of 3 with deadheart (%) between 21 and 30; 17 genotypes classed in scale rating of 4 had deadheart (%) between 31 and 40. There are 4 sorghum genotypes that received a 5 rating implying a deadheart percentage between 41 and 50. Management of sorghum stem borer revealed that standard check, Carbofuran 3.0 %CG @ 8.2 kg/ha was found to be superior to all the treatments in terms of plant vigour (rating of 1.00), deadheart formation (5.49%) and green fodder yield (309.60 q/ha) and was statistically at par with egg parasitoid, Trichogramma chilonis @ 75000 parasitized eggs/ha that recorded the values, 1.33 scale rating, 6.34%, 320.8 q/ha for afformentioned parametres. However, the maximum ICBR was noticed in treatment received application of egg parasitoid, Trichogramma chilonis (2.79) followed by standard check, Carbofuran 3.0% CG (1.22).