Overwintering sites and strategies of Culex quinquefasciatus (Diptera: Culicidae) larvae and impact of neem seed kernel aqueous suspension (NSKAS) and other eco-friendly tools on them

Vimla Thareja; Anina James; Rangoli Singh; Anjana Singha Naorem; Manisha Pandey; Zeba Khan; Souvik Sensharma; Stuti Mohapatra

Overwintering sites and strategies of Culex quinquefasciatus (Diptera: Culicidae) larvae and impact of neem seed kernel aqueous suspension (NSKAS) and other eco-friendly tools on them

Author(s): Vimla Thareja, Anina James, Rangoli Singh, Anjana Singha Naorem, Manisha Pandey, Zeba Khan, Souvik Sensharma and Stuti Mohapatra

Abstract: Larval sites of Culex quinquefasciatus Say were discovered outdoor in urban environment, during winters (2006-2015). In these sites prolongation of the larval period to ~28 days was major overwintering strategy of larvae and 40% mortality was observed during larval period. Prolongation provided a long duration for elaborate study of their biological traits. Introduction of Gambusia affinis in one site showed its predatory role and induced deterrence to oviposition of Cx.quinquefasciatus during winter.

Effect of neem seed kernel aqueous suspension (NSKAS), concentrations 625-10,000 ppm was studied on overwintering fourth instar larvae under field conditions for two years. At low concentrations, effect at 24 h was sublethal; post 24 h manifestations exhibited as severe deformities and mortality. Treated larvae showed no antifeedancy, rectal prolapse, anal gills shrinkage and shedding, air bubbles around tracheae, convulsions, leading to mortality evidencing NSKAS as stomach, respiratory and nerve poison. Larval-pupal intermediates indicated moulting disruption. Use of NSKAS, G. affinis or source reduction of larvae are eco-friendly tools suggested for Integrated Vector Management (IVM) during winter, on priority basis.

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Larval mortality at 24 h and total larval mortality after treatment with NSKAS in 2013-2014. Significant differences (<em>P</em><0.05) between means when compared with control are denoted using * for mortality at 24 h and # for total mortality.

Fig.: Larval mortality at 24 h and total larval mortality after treatment with NSKAS in 2013-2014. Significant differences (P<0.05) between means when compared with control are denoted using * for mortality at 24 h and # for total mortality.

Pages: 135-141 | 2574 Views 131 Downloads

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Vol. 4, Issue 2, Part B (2017)

Overwintering sites and strategies of Culex quinquefasciatus (Diptera: Culicidae) larvae and impact of neem seed kernel aqueous suspension (NSKAS) and other eco-friendly tools on them

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