Biointensive management of greenhouse whitefly, Trialeurodes vaporariorum (Westwood) on cucumber under protected environment
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Date
2021-10-22
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Palampur
Abstract
Investigations on “Biointensive management of greenhouse whitefly, Trialeurodes vaporariorum (Westwood) on
cucumber under protected environment” at Palampur, 1290 m asl were undertaken to determine the lethal toxic
and deterrent activity of natural and organic products to different developmental stages of greenhouse whitefly.
Natural and organic products namely Darekastra, Dashparni, fermented buttermilk, fermented cow urine,
Tamarlassi and vermiwash were evaluated for determining their insecticidal properties viz., lethal toxic (ovicidal,
nymphicidal and adulticidal) and deterrent (repellent and oviposition deterrent) and to evaluate their efficacy for
the management of greenhouse whitefly on cucumber under naturally ventilated polyhouses. Natural and organic
products resulted in toxicity of 5.09 to 55.93 %, 1.67-62.96 % and 3.33-85.19 % to eggs, nymphs and adults,
respectively, in the concentration range of 1.25 to 40.00 % with lethal median toxicity (LC50) varying from 9.34 to
25.15 %, with the minimum and maximum corresponding to Tamarlassi and vermiwash, respectively. The
repellence of natural products at recommended field dose (10.00 %) to greenhouse whitefly adults varied from
28.53 to 71.64 % and 15.22 to 41.21 % in choice and no-choice tests, respectively depicting Tamarlassi and
vermiwash to be most and least repellent natural and organic product. They also exhibited oviposition deterrent
activity varying between 24.32 to 47.27 % and 24.30 to 43.23 % in choice and no-choice test, respectively with
the highest value corresponding to Tamarlassi (in both) and lowest to Darekastra (in choice test) and vermiwash
(in no-choice test), respectively. Insecticidal properties of natural and organic products categorized on the basis of
lethal toxic and deterrent properties at recommended field dose revealed Tamarlassi to possess moderate level of
insecticidal activity. Fermented buttermilk, fermented cow urine and Dashparni exhibited low level of insecticidal
activity. However, Darekastra and vermiwash exhibited very low to low level of insecticidal activity. Efficacy of
bioagent, natural products and insecticides against T. vaporariorum on cucumber under protected environment
was evaluated as preventive and curative measures. In preventive measures, soil application of imidacloprid
(0.009 %) was the most efficacious and was followed by foliar application of azadirachtin (0.00045 %). Among
natural and organic products, Tamarlassi (10 %) was the most efficacious. In curative measures, alternate
application of spiromesifen (0.02 %) and thiamethoxam (0.008 %) proved most efficacious against nymphs of T.
vaporariorum and was followed by soil application of imidacloprid. Among natural and organic products,
Tamarlassi proved to be most efficacious and was followed by fermented buttermilk and fermented cow urine.
Alternate foliar application of spiromesifen and thiamethoxam proved most efficacious in reducing adult
population when used as curative measures. It was followed by soil application of imidacloprid. Among natural
and organic products, Tamarlassi proved most efficacious and was followed by fermented cow urine. and alternate
foliar application of vermiwash & Tamarlassi. Parasitoid, Encarsia formosa parasitization was influenced by
different products significantly and was maximum in vermiwash. Tamarlassi recorded minimum number of
mummified nymphs. Among chemical insecticides, alternate application of spiromesifen and thiamethoxam
resulted in minimum number of mummified nymphs. Yield of cucumber fruits obtained in preventive measures
was maximum in the treatment comprising foliar application of fermented cow urine whereas in curative
measures, it was maximum for alternate foliar application of spiromesifen & thiamethoxam. Net returns were
higher in preventive management measures for all the natural and organic products. Incremental cost benefit ratio
worked out was maximum for soil application of imidacloprid (22.94) and was followed by alternate application
of spiromesifen and thiamethoxam (13.91). Amongst natural products, fermented cow urine resulted in highest
incremental cost benefit ratio (9.54) and was followed by Tamarlassi (7.10).