EVALUATING THE RESPONSE OF ANOPHELES COLUZZII AND CULEX QUINQUEFASCIATUS MOSQUITO LARVAE TO SODIUM CHLORIDE AND DETERGENT POWDERS IN SEMI-FIELD CONDITION IN NIGERIA

Abstract

Sodium chloride (NaCl) and detergent solution have been evaluated for mosquito larvae in laboratory studies but there is no evaluation for powdery salt and detergent. Therefore, this current study evaluated the response of Anopheles coluzzii and Culex quinquifasciatus larvae to salt and detergent powders in semi-field experiments. Anopheles and Culex larvae were collected from the wild fields. Twenty larvae were introduced into 100ml of water with 1g, 2.5g, 5g, 10g & 15g of salt and detergent. These corresponded to 0.01g/ml, 0.025g/ml, 0.05g/ml, 0.1g/ml &0.15g/ml respectively. The experiment was replicated into ten. Analysis of variance test was used for significance and Probit model analysis was used to predict lethal concentrations for 50% and 95%. Mean toxicity of larvae increased as concentration increased in all the treatments. Cx. quinquifasciatus and exposed to 10g and 15g of salt and detergent recorded complete toxicity. The differences between Culex and Anopheles mosquitoes exposed to salt and detergent were significant (p<0.05). Complete mortality was recorded in all but at different time. Complete mortality in Culex and Anopheles exposed to 15g of salt and detergent was after 10 minutes. Irrespective of the species, lethal time for 50% of mosquitoes ranged from 5.0 to 1560.8 minutes whereas LT95 range from 6.3 to 1893.3 minutes for salt and detergent exposure. Culex exposed to detergent recorded the lowest lethal time. So, the salt and detergent at best concentrations were effective and treated abandoned mosquito breeding site.