EVALUATION OF ONION GENOTYPES AGAINST ONION THRIPS, Thrips tabaci LINDEMAN AND ITS MANAGEMENT THROUGH BOTANICALS
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Date
2016
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Indira Gandhi Krishi Vishwavidyalaya, Raipur
Abstract
Thereafter the population was gradually declined from
51st SMW, respectively. The majority of insect pests showed positive correlation with
ambient temperature, relative humidity, wind velocity, sunshine hours and rainfall. Major
insect pests in relation to predators viz., green lacewing, lady bird beetle and spiders were
recorded during the crop growth period and showed highly significant correlation with thrips
and jassid while non significant correlation with tobacco caterpillar and cricket population.
In the study, 40 genotypes of onion including check variety Agrifound dark red as
susceptible check were evaluated against incidence of thrips, Thrips tabaci L., Out of 40
genotypes, 8 genotypes were categorized as highly resistant, 10 as resistant, 17 as susceptible
and 5 as highly susceptible to onion thrips. The genotype ON14-13 (3.03 thrips/plant) was
considered as highly resistant followed by OSK-1306 (3.53 thrips/plant), ON14-01 (3.63
thrips/plant), and OSK-1301 (3.90 thrips/plant) because of lowest thrips population score and
were superior with check variety Agrifound dark red. Genotype ON15-11 (17.64 thrips/plant)
was highly susceptible than the check variety Agrifound dark red of onion.
Maximum average weight loss per bulb (71.25%) was observed in the genotype
ON15-11 followed by ON14-04 (55.97%) and ON14-23 (53.15%) with the minimum weight
loss per bulb (2.70%) was recorded in the genotype OSK-1301 followed by OSK-1329
(5.40%). Maximum average loss in diameter per bulb (48.88%) was observed in the genotype
ON15-11 followed by ON14-15 (33.52%) and ON14-23 (31.78%). The minimum loss in
diameter (1.52%) was recorded in genotype OSK-1339 followed by ON15-04 (3.28%).
Assessment of yield losses clearly pointed out that if pest is not managed properly, the losses
caused due to the incidence of thrips from 1.5 to 43.31 % in yield depending upon the climate
and area.
Efficacy of botanicals against thrips on onion crop revealed that the spray of NSKE
5% followed by Neem oil 2% was the most effective against thrips as it recorded lowest
thrips population (6.61thrips/plant) and (6.90 thrips/plant), respectively. However, Aak leaves
extract was least effective as it recorded highest 15.09 thrips population per plant.
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109 p.