ABSTRACT
Susceptibilities of two colonies of the taxon An. dirus (one from Perlis and from Thailand) and one colony of An. balabacensis from Sabah to DDT, dieldrin, malathion, fenitrothion and propoxur were determined. DDT and fenitrothion tolerance was found in An. dirus species B and An. balabacensis. No resistant strain was isolated as the two colonies were not either homozygous or nearly so for resistance. Field testing of the susceptibility of the adults of An. balabacensis to DDT was carried out between 1957 to 1976. The results indicated a progressive rise in the LC50 levels greater than 1% in almost all instance. The variation in the number of sprays applied in some districts have resulted in varying sensitivities. Association between the changes in levels of DDT susceptibility and exophilic habit of An. balabacensis has been observed but needs further confirmation. The significance of these findings and the difficulties in distinguishing tolerant from truly resistant individuals are discussed in relation to accurate species identification.
Subject(s)
Animals , Anopheles/drug effects , DDT/pharmacology , Dieldrin/pharmacology , Disease Vectors/drug effects , Female , Fenitrothion/pharmacology , Insecticide Resistance , Insecticides/pharmacology , Malathion/pharmacology , Male , Propoxur/pharmacologyABSTRACT
The susceptibility of adults Tribolium confusum, Tribolium castaneum, Sitophitus granarius and 4th instar Larvae of Trogoderma granarium, vectors of tapeworms, to Baythion Fenthion, Folithion and Diazinon was determined by direct exposure to treated disks of jute. As the tested insects succumbed evidently to Baythion in addition to its lower mammalian toxicity compared with Malathion the former may be considered in replacing the latter for potential, direct spray and residual surface applications