engleski

Residual film method and modified residual film methods used to evaluate toxicity of three pesticides on Tribolium castaneum

Tribolium castaneum, the red flour beetle, is one of the major pests of stored products. It is a very prolific, long-lived species quite resistant to eradication which cultures can be maintained indefinitely on a simple medium of flour and yeast. These traits make them easy to culture and manipulate in the laboratory. Therefore, it has been used largely as animal model in population ecology and toxicology. Infestation of food products with this species can be controlled with usage of insecticides. The most common method used to investigate the effects of pesticides to Tribolium castaneum is residual film method (RFM). This laboratory study was undertaken to investigate effects of exposure to three widely used pesticides (dimethoate, pirimiphos-methyl and deltamethrin) using Tribolium castaneum adults as model organisms. The toxicity of these pesticides was investigated using RFM and modified RFM. Namely, in the original RFM organisms are in direct contact with the pesticide and have difficult to move across the glass bottom of the petri dishes. In order to make exposure conditions more suitable for these insects, in modified RFM adults were exposed to pesticides in combinations with flour. On the basis of calculated LC10, LC50 and LC90 values pirimiphos-methyl showed the highest toxicity and according to the toxicities the investigated pesticides could be arranged in the following order: pirimiphos- methyl>deltamethrin>dimethoate. Additionally, the results of this study showed different toxicities of pesticides depending on the exposure methods. Namely, after exposure of insects using modified RFM the mortality was significantly reduced. Survival curves estimated according to the Kaplan–Meier product-limit method showed higher survival probability for modified RFM compared to original RFM. The obtained results could be possibly explained with usage of flour which served as base on which Tribolium castaneum could move more easily as well as a barrier between organism and pesticide.

dimethoate ; pirimiphos-methyl ; deltamethrin ; red flour beetle ; survival

nije evidentirano