Selectivity of fungi used in pest control to Africanized Apis mellifera L. (Hymenoptera: Apidae)

Abstract

Side effects of fungi used for pest control on Apis mellifera, such as longevity and behavior should be made because these bees are beneficial to pollination. The objective was to evaluate the effects of commercial biological products, based on fungi, on the longevity and displacement behavior of Africanized bees A. mellifera. Different bioassays were carried out: 1) Ingestion of products; 2) Topical application by spraying; 3) Insect contact with the treated surface; 4) Residual effect and behavior analysis. The treatments were Control (distilled water), Beauveria bassiana; Isaria fumosorosea; Metarhizium anisopliae and Trichoderma harzianum. In bioassay 1, B. bassiana was the product that most reduced the longevity of bees by 39% after 168 h of evaluation. In bioassay 2, the product I. fumosorosea reduced the survival of bees, where only 5% of the bees were alive after 68 h. The other treatments did not affect the survival of A. mellifera workers. In bioassay 3, there was a reduction in the survival of worker bees of A. mellifera, from treatments B. bassiana and I. fumosorosea, after 168 h. These two products showed residual effects three and six days after application. In the vertical displacement, none of the products interfered, in the fall, all the products interfered. And in walking, no treatment interfered with the evaluated parameters. Of the tested fungi in the laboratory, T. harzianum was the selective fungus, for the Africanized A. mellifera workers, being considered safe. The other fungi were less selective in laboratory bioassays on Africanized A. mellifera workers.