EFFET D’UN INSECTICIDE UTILISÉ EN PROTECTION DES VÉGÉTAUX: THIAMETHOXAM SUR L’ABEILLE SAHARIENNE Apis mellifera sahariensis

Abstract

The use of plant products in the fight against agricultural pests has become a necessity. But this mean of control is not risk free and may result in unintended consequences such as toxicity in non-target organisms. Of these, honeybees play a triple role, agronomic, economic and ecological. Actara 25 WG, a commercial preparation containing Thiamethoxam, is recognized as toxic to bees and is prohibited from use during the period of flowering. However, this commercial product is systemic, it is therefore present in low concentrations in the treated plant throughout its development cycle. The effects induced in the bee by the contamination by low doses of Thiamethoxam that may be contained in the pollen and nectar at flowering timeare the subject of this study. To resolve this problem, first the sensitivity of the Saharan honeybee Apis mellifera sahariensis was evaluated. This was based on testing the acute oral toxicity of thiamethoxam on worker bees in the laboratory, which is the basis of toxicological risk assessment. The study is based on determining the oral LD50. Bees of unknown age were fed a sucrose solution supplemented with doses of the insecticide used (1, 10, 20, 50, 70, 90 ng of active substance per bee). For the duration of the study the control and treated bees were placed in the dark at a temperature of 25 ± 2 ° C and 60% relative humudité. The result showed that the LD50 obtained varied between 10.86 and 11.47 ng per bee.