Biorational management of sorghum shoot fly, Atherigona soccata Rondani in forage sorghum
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Date
2020
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Punjab Agricultural University, Ludhiana
Abstract
Ecofriendly strategies for the management of shoot fly, Atherigona soccata helps in addressing the issues
related to insecticides load on forage crop. The serial sowing technique at different time of intervals was
used, starting from 2nd fortnight of March (12th SMW) to 1st fortnight of July (27th SMW). Oviposition per 10
plants and deadheart percentage recorded to be low in 18th SMW (1st fortnight of May) sown crop (6.66:
oviposition & 25.46 %: deadheart), but found to be the highest in 1st fortnight of July (27th SMW) sown crop
(21.95: oviposition & 65.45%: deadheart) in unprotected plots. The correlation of shoot fly infestation in
relation to weather parameters revealed that egg load and deadhearts were negatively correlated with
maximum temperature and positively correlated with minimum temperature, relative humidity and rain fall.
Green fodder yield was recorded to be the highest for the crop sown on 1st fortnight of May (409 q/ha).
Different non chemical approaches for effective management of A. soccata depicted that fermented fish meal
extract + Cypermethrin 10 EC has lowest DH percentage (19.37 %) followed by Malathion 50 EC spray
(22.79 %) in comparison to other treatments (38.70, 35.62, 33.37 and 43.37 % in higher seed rate +
proportionate fertilizer, higher seed rate + biofertilizer and recommended seed rate + biofertilizer and
untreated control respectively). Egg load per 10 plants was also recorded to be low (9.29) in treatment of
fermented fish meal extract + cypermethrin 10 EC spray as compared to untreated control (15.00). Green
fodder yield (q/ha) was also recorded maximum in this promising treatment followed by Malathion 50 EC
(399), whereas low yield was obtained in plots with higher seed rate irrespective of seed treatment with
consortium biofertilizer and proportionate fertilizer application. Timely control of shoot fly is utmost
important to maintain high plant population, delay in insecticides application adds more to yield losses. Seed
treatment with thiamethoxam 30 FS at varying doses i.e. 8, 10 and 12 ml/kg seed individually and in
combination with spray of Malathion 50 EC or NSKE 1500 ppm on seed treated plots helped in effective
management of shoot flies. Significantly lower infestation of shoot fly (9.41-21.54 % DH) across different
insecticides treatments was recorded as compared to untreated (48.66 % DH) and standard check (27.54 %
DH). Superiority of thiamethoxam 12 ml/kg seed + Malathion 50 EC sprayed plot was supported by lowest
deadheart percentage (9.41 %) in comparison to standard check (27.54 %) and the highest deadheart
reduction over control (79.34 %) was also high in this treatment followed by thiamethoxam 12 ml/kg seed +
NSKE 1500 ppm sprayed plots (76.77 % ) in comparison to standard check (39.53 %). Larval survival
percentage was observed to be the lowest in thiamethoxam 30 FS @ 12 ml/kg seed + Malathion 50 EC spray
(28.33 %) followed by thiamethoxam 30 FS @ 12 ml/kg seed + NSKE 1500 ppm (31.67 %) in contrast to
untreated control (90.00 %). GFY (q/ha) was also recorded highest in seed treated with thiamethoxam 30 FS
@ 12 ml/kg seed + Malathion 50 EC sprayed plots (492) as compared to standard check (400) and untreated
control (347). Economic analysis of different treatments revealed that protection against shoot fly damage as
seed treatment alone and combined with insecticides spray at 20 DAG lead to yield advantage of 98-145
q/ha as compared to standard check (53 q/ha) and the promising treatment (thiamethoxam 30 FS @ 12 ml/kg
seed + Malathion 50 EC) yielded net return of Rs. 19729/ha.