INTEGRATED MANAGEMENT OF ONION THRIPS, Thrips tabaci LINDEMAN (THYSANOPTERA: THRIPIDAE)
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Date
2019-03
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University of Horticultural Sciences, Bagalkot
Abstract
The present investigation on the integrated management of onion thrips, Thrips
tabaci Lindeman (Thysanoptera: Thripidae) was conducted during 2017-18 at Haveli
farm, University of Horticultural Sciences, Bagalkot (Karnataka). Field evaluation of
bio-inoculants, organic amendments and biorationals against onion thrips revealed that,
two sprays of Lecanicillium lecanii (2 x 108 CFU/g) @ 2.0 g/l and azadirachtin 1500
ppm @ 3.0 ml/l at ten days interval were found to be superior in suppressing thrips
population and also found safer to coccinellids and spiders prevailing in the cropping
ecosystem. Further, L. lecanii @ 2.0 g/l recorded maximum yield (18.78 t/ha) and
highest B:C ratio (2.67). The results obtained from biochemical analysis of the plants
which received different bio-inoculants, organic amendments and biorationals against
onion thrips revealed that the foliar application of Pseudomonas fluorescens @ 5.0 g/l
found to enhance the resistance in onion plants as it was indicated higher amount of
phenols and tannins as against other treatments. The field experiment on bio-efficacy of
synthetic insecticides against onion thrips revealed that, three sprays of thiamethoxam
25 WG @ 25 g a.i./ha and imidacloprid 17.8 SL @ 22.25 g a.i./ ha at ten days interval
were found to be superior in managing thrips on onion crop. Further, thiamethoxam 25
WG @ 25 g a.i./ha recorded maximum yield (25.39 t/ha), highest B:C ratio (3.58) and
also found safer to the natural enemies as that of other evaluated insecticides. Among
the different IPM modules evaluated against onion thrips, chemi-intensive module and
adaptable IPM module were found to be superior in reducing thrips population.
Whereas, adaptable IPM module comprising of soil application of neem cake @ 250
kg/ha at the time of transplantation, followed by foliar spray of P. fluorescens @ 5.0 g/l
at 15 DAT, followed by lambda cyhalothrin 5 EC @ 12.50 g a.i./ ha at 25 DAT, L.
lecanii @ 2.0 g/l at 35 DAT, thiamethoxam 25 WG @ 25 g a.i./ ha at 45 DAT recorded
maximum yield (28.50 t/ha) and B:C ratio (3.51) as that of chemi-intensive module.
Further, it found to be an effective, economical and relatively safer module. Hence,
adaptable IPM module can be recommended for managing thrips on onion crop.