Toxicity of pesticides used in citrus crop to Apis mellifera/Toxicidade de produtos fitossanitarios utilizados em citros para Apis mellifera

The aim of this research was to evaluate the toxicity of several acaricides/insecticides used in Brazilian citrus crop to africanized workers of Apis mellifera Linnaeus. The exposition of honey bees to the chemicals was performed by direct spraying, contamination of food, and contact in treated surface (citrus leaves and Petri dishes), using recommended rates of application. The assays were carried out at 25 ± 2 °C, RH 70 ± 10%, 12h of photophase and the data was statistically analyzed, with mean values of mortality being compared through cluster analysis. In all assays acephate was highly toxic, with mortality at 24 hours around 90.0%. When spirodiclofen and pyriproxyfen, was sprayed directly into the honeybees, they caused mortality levels of 11.0 and 15.0%, respectively; buprofezin, sulphur and tetradifon were less toxic, with mean mortality of 5.0% among these compounds. For the assays from contamination surface (citrus leaves and Petri dishes) and food, two groups of chemicals with the same toxic effects were observed, one with acephate and other with buprofezin, sulphur, spirodiclofen, pyriproxyfen, tetradifon and water. The average mortality after 96 hours of exposition was 31.0; 8.3 and 15.7%, respectively, for each method of contamination. Key words: africanized honey bee, orange, pesticide, mortality. O objetivo deste trabalho foi avaliar a toxicidade de inseticidas/acaricidas utilizados em cultura de citros para operarias africanizadas de Apis mellifera Linnaeus. A exposicao das abelhas aos compostos foi realizada usando-se tecnicas de pulverizacao, contaminacao da dieta e contato em superficies tratadas (folhas de citros e placas de Petri), empregando-se as doses maximas recomendadas para a cultura. Os bioensaios foram realizados em laboratorio a 25 ± 2 °C, UR 70 ± 10% e fotofase de 12h, sendo os dados de mortalidade submetidos a analise estatistica, e as medias comparadas por contraste, obtendo-se grupos de efeitos semelhantes. Independente do modo de exposicao, o acefato foi extremamente toxico, matando mais de 90,0% das abelhas 24h apos a aplicacao. Os produtos espirodiclofeno e piriproxifem, quando aplicados diretamente sobre as abelhas, causaram niveis de mortalidade de 11,0 e 15,0%, respectivamente; os compostos buprofezina, enxofre e tetradifona apresentaram niveis de mortalidade ainda menores, com media de 5,0% entre eles. Para os ensaios de contaminacao de superficie (folhas de citros e placas de Petri) e contaminacao de alimento, fora