Bioefficacy of mycopathogensVerticillium lecanii Zimmermen andMetarhizium anisopliae Metchnikoff against sucking pests of Bt cotton

Abstract

Entomopathogenic fungi Verticillium lecanii Zimmermen and Metarhizium anisopliae Metchnikoff have generated a great deal of interest in recent years because of their potential as bio-control component in integrated pest management of cotton. These two mycopathogens were evaluated against sucking pests of Bt cotton during Kharif 2011 and 2012 at Cotton Improvement Project, Mahatma Phule Krishi Vidyapeeth, Rahuri to find out the scope and potentiality of V.lecanii and M.anisopliae against sucking pests of Bt cotton in intra hirsutum Bt hybrid (RCH-2Bt). Mycopathogens V.lecanii (2 x 10 8 cfu/gm and 2 x 10 12 cfu/g) and M.anisopliae @ 2000 g/hectare were evaluated alone and in combination (V.lecanii + M.anisopliae). The observations were recorded on 3,5 and 10 days interval after each spray application. Pooled analysis of two years data revealed that V.lecanii (2 x 10 12 cfu/g) @ 2000 g/hectare + M.anisopliae (2 x 10 12 cfu/g) @ 2000 g/ha in combination was found more effective and significantly superior to its lower dose V.lecanii (2 x 10 8 cfu/g)@ 2000 g/ha + M.anisopliae (2 x 10 8 cfu/g) @ 2000 g/ha. It was proved superior over all other treatments in reducing aphids, jassids, thrips and whitefly population, however, it was at par with V.lecanii (2 x 10 12 cfu/g) @ 2000 g/ha. Thus, V.lecanii (2 x 10 12 cfu/g) @ 2000 g/ha was found to be the effective dose against all major sucking pests of cotton. Investigation on evaluation of entomopathogenic fungi against natural enemies of sucking pests in Bt cotton revealed that there was no significant adverse impact of V. lecanii and M. anisopliae on the activity of natural enemies viz., Chrysoperla and Coccinellids; when compared with the population of natural enemies in control. Sole and combine application of V. lecanii and M.anisopliae at all the evaluated doses were not found toxic to natural enemies.

Assessment of Lecanicillum lecanii (Zimmermen) against sucking pests in Bt cotton

“…Ghelani et al (2006; found that V. lecanii @ 5 g/ l was effective against Aphis gossypii; and V. lecanii @ 2.5 kg/ ha combined with azadirachtin @ 0.0009% were found moderately effective against major sucking pests of Bt cotton. Raghunandan et al (2018) observed that sucking pests in cotton get reduced significantly with spraying of V. lecanii @ 4 g/ l. Hole et al (2015) observed effectiveness of V. lecanii (2 x 10 12 cfu/g) @ 2000 g/ ha against sucking pests in Bt cotton. Wawdhane et al ( 2020) also observed such effectiveness.…”

Comparative efficacy of novel insecticide molecules against sucking pests in cotton

“…Bt cotton is highly vulnerable to sucking pests which spread throughout the growing season, as the biotic potential of these sucking pests are high they are potential threat to Bt cotton. Farmers generally use old generation molecules which are hazardous to mammals and ecosystem [6][7][8][9][10][11][12] . Although resistance to neonicotinoids was slow to develop, several insect pests including Aphis gossypii have been shown to possess a potential for resistance development.…”