Vol. 11, Issue 9 (2022)

Author(s):
Sujay Pandey, MK Pathak, MK Pandey, Satyendra Singh and PK Gupta

Abstract:
Onion thrips causes 30–50% reduction in bulb yield during severe infestation. If onion thrips are not controlled, damage can routinely reduce bulb yield by 23-85%. In spite of all recommended insecticides onion thrips survives between the leaves in deep, due to this some of these were not affected during spray and remains live results in large scale multiplication. Surfactant reduces the surface tension of spray solution and gives an ideal coverage and penetration between the leaves. In addition to this, surfactants solubilize, suspend and disperse the active ingredient of pesticide. Therefore, the present study was carried out to find out the role of silica based surfactant in the efficacy of insecticides against onion thrips during two consecutive years i.e. rabi, 2017-18 and 2018-19 seasons on onion variety NHRDF Red at Regional Research Station, NHRDF, Karnal (Haryana). The combined data revealed that the lowest thrips population (7.94 nymphs/plant) was recorded in treatment Fipronil 5% SC @ 1.0 ml/L + Surfactant (silica based) @ 0.5 ml/L water) and the highest population (16.97 nymphs /plant) was noted in control. The highest gross and marketable yields (278.52 q/ha and 258.0 q/ha) were recorded in treatment Fipronil 5% SC @ 1.0 ml/L + Surfactant (silica based) @ 0.5 ml/L water and were found at par with treatment Fipronil 5% SC @ 1.0 ml/L + Sever Surfactant (non-silica based) @ 0.5 ml/L. The lowest gross and marketable yields (231.80 q/ha and 212.27 q/ha) were recorded in treatment control. The highest B:C ratio (6.73:1) was recorded in treatment Fipronil 5% SC @ 1.0 ml/L + Sever Surfactant (non-silica based) @ 0.5 ml/L.