Evaluation of insecticides against cotton mealybug, Phenacoccus solenopsis Tinsley and their safety to important predators

254-262Cotton plays an important role in the world economy by supplying raw materials to different manufacturing units. Of late, it is being seriously attacked by the cotton mealybug, Phenacoccus solenopsis Tinsley. The biological control involving coccinellid beetles and chrysopids as predators could lead to ecologically sustainable mealybug control. Here, in the context of conservation of natural enemies, we exploredthe efficacy of insecticides on the cotton mealybug and also safety to other predators. Six insecticides viz; chlorpyrifos 20 EC (0.05%), endosulfan 35 EC (0.07%), monocrotophos 36 SL (0.04%), malathion 50 EC (0.12%), dichlorvos 76 EC (0.15%), and alphamethrin 10 EC (0.01%) were tested for their residual toxicity against the mealybug, P. solenopsis and its coccinellid predators. Studies revealed that, both chlorpyrifos and malathion showed highest toxicity in terms of mean mortality (100%) to female mealybugs at 24 h of exposure as against lowest in endosulfan (35%). Interestingly, chlorpyrifos and dichlorvos, which proved toxic to mealybug were less toxic to the grubs of Cryptolaemus montrouzieri, registering only 21.66 per cent and 34.16 per cent mortality, respectively. These insecticides when offered to the adults along with honey differed in toxicity as stomach poison at 24 hrs of exposure. Endosulfan registered mortality to the tune of 60 and 70% against Coccinella septempunctata and Cheilomenes sexmaculata, respectively. However, stomach toxicity pertaining to the insecticide-sprayed mealybugs as prey offered to all the three species of predators indicated that the insecticides, chlorpyrifos and endosulfan were lesser toxic to these wherein mean mortality ranged from 38.09 to 56.66 and 50 to 65.71%, respectively. Dichlorvos was the most toxic, registering 100% mortality for all 3 predators viz. Nephus regularis, Scymnus coccivora and Hyperaspis maindroni. The release of C. montrouzieri coupled with chlorpyrifos is likely to be a better option for the management of mealybugs infesting several agri-horticultural crops

Evaluation of insecticides against cotton mealybug, Phenacoccus solenopsis Tinsley and their safety to important predators

Cotton plays an important role in the world economy by supplying raw materials to different manufacturing units. Of late, it is being seriously attacked by the cotton mealybug, Phenacoccus solenopsis Tinsley. The biological control involving coccinellid beetles and chrysopids as predators could lead to ecologically sustainable mealybug control. Here, in the context of conservation of natural enemies, we exploredthe efficacy of insecticides on the cotton mealybug and also safety to other predators. Six insecticides viz; chlorpyrifos 20 EC (0.05%), endosulfan 35 EC (0.07%), monocrotophos 36 SL (0.04%), malathion 50 EC (0.12%), dichlorvos 76 EC (0.15%), and alphamethrin 10 EC (0.01%) were tested for their residual toxicity against the mealybug, P. solenopsis and its coccinellid predators. Studies revealed that, both chlorpyrifos and malathion showed highest toxicity in terms of mean mortality (100%) to female mealybugs at 24 h of exposure as against lowest in endosulfan (35%). Interestingly, chlorpyrifos and dichlorvos, which proved toxic to mealybug were less toxic to the grubs of Cryptolaemus montrouzieri, registering only 21.66 per cent and 34.16 per cent mortality, respectively. These insecticides when offered to the adults along with honey differed in toxicity as stomach poison at 24 hrs of exposure. Endosulfan registered mortality to the tune of 60 and 70% against Coccinella septempunctata and Cheilomenes sexmaculata, respectively. However, stomach toxicity pertaining to the insecticide-sprayed mealybugs as prey offered to all the three species of predators indicated that the insecticides, chlorpyrifos and endosulfan were lesser toxic to these wherein mean mortality ranged from 38.09 to 56.66 and 50 to 65.71%, respectively. Dichlorvos was the most toxic, registering 100% mortality for all 3 predators viz. Nephus regularis, Scymnus coccivora and Hyperaspis maindroni. The release of C. montrouzieri coupled with chlorpyrifos is likely to be a better option for the management of mealybugs infesting several agri-horticultural crops

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Not AvailableStem borer Stromatium barbatum (F.) (Coleoptera: Cerambycidae) has emerged as a major pest in grapes in India. In the present study, the chromosome number and basis of sex differentiation of S. barbatum are described. Mitotic chromosome spreads were prepared by isolating and treating the gonads with colchicine and staining with conventional Giemsa stain. Cytogenetical analysis revealed the events of chromosomal evolution. The results revealed diploid chromosome number of 2n = 18+XO in male and 2n = 18+XX in female. Presence of supernumerary chromosome in female, translocation and uncommon pairing behaviour also were observed. The differences and similarities of the sexes are brought out.Not Availabl

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Not AvailableThe mango fruit borer, Citripestis eutraphera (Meyrick), originally confined to the Andaman Islands, is a recent invasion in mainland India. With changes in climatic conditions, the pest is likely to spread in other major mango-growing regions of the country and can pose serious threats to mango production. In this backdrop, the present study examines the impact of climate change to develop spatio-temporal distribution of invasive C. eutraphera in India using the maximum entropy (MaxEnt) modelling approach. Integration of point data on current occurrence of pest and corresponding bioclimatic variables in MaxEnt were used to define the potential distribution in India and mapped using spatial analysis tool in ArcGIS. The model framework performed well as indicated by high area under the curve (0.97) value. Jackknife test for estimating predictive power of the variables indicated that ‘isothermality’ and ‘temperature seasonality’ significantly affected C. eutraphera distribution. It was found that mango-growing pockets in the southwestern parts of Gujarat, as well as parts of Kerala and Tamil Nadu were moderately to highly suitable for C. eutraphera distribution in 2050 and 2070. The results of this study could be an important guide for selecting monitoring and surveillance sites and designing integrated pest management policies in the context of climate change against this invasive pest of mango.Not Availabl

NIASM Annual Report 2015-16

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