Search

Bacillus thuringiensis (Bt), an entomopathogenic bacterium, has been used as bioinsecticides for insect pest control worldwide. Consequently, the objective of this work was to evaluate the possible effects of commercial formulations of Bt products, Dipel and Xentari, on the survival and behavior of Africanized honey bees (Apis mellifera). Bioassays were performed on foragers and newly emerged (24-h-old) bees that received the products mixed in the food. Their survival and behavior were evaluated through the vertical displacement tests and the walk test, analyzed using software Bee-Move. Then, histological analysis of the mesenterium was performed. As control treatment was used sterile water. The honey bees' survival was evaluated for between 1 and 144 h. No interference of B. thuringiensis, Dipel and Xentari, in the survival of Africanized honey bees were found. Only Xentari interfered with vertical displacement behavior of newly emerged (24-h-old) bees. Both the products tested were selective and safe for A. mellifera.

Canola has a long period of flowering in the winter season and this, associated with the lack of other flowers and the use of insecticides to control insect pests, means it may have a great impact on bee populations, such as Apis mellifera L. (Hymenoptera: Apidae). In this context, the use of insecticides with lower residuals and less harmful effects to bees is fundamental. Thus, the objective of the current work was to evaluate, in a laboratory bioassay, the residual toxicity and effect of imidacloprid, beta-cyfluthrin, and a mixture of both, when applied on canola in the field, on Africanized A. mellifera workers. Three commercial products were applied, formulated with imidacloprid, beta-cyfluthrin, and beta-cyfluthrin + imidacloprid. Each plot received one of the three treatments, in the concentration recommended by the manufacturer, at intervals between 14 and 0 days prior to conducting the bioassays. On the day of the bioassay, the bees were exposed to the plant material containing the treatments for a period of two hours, and were transferred to PVC cages, containing food and water. Mortality assessments were then performed at pre-established intervals until a 96 h post-exposure. Residuals on canola leaves of all tested products caused a significant reduction of honeybee worker longevity, which was less accentuated when the interval after treatment application increased. Safer pest management strategies are needed to ensure the preservation of bees. [ABSTRACT FROM AUTHOR]

Bees are fundamental insects in agroecosystems, mainly due to pollination. However, its decline has been observed in recent years, and the contamination by pesticides is suspected to be responsible. This relationship is the objective of our research, which is the first scientometric study on this subject. The data were obtained from the Web of Science database (1231) and were analyzed using Microsoft Office Excel and CiteSpace. The results point to a significant increase in pesticide and bee reseach in the last 15 years in the most influential scientific journals. The USA and France have the largest number of publications and a moderade relationship between this trait and GDP (gross domestic product) was observed (r = 0.80; r2 = 0.60). There is no correlation between the use of pesticides and studies of the effects on pollinators and the use of pesticides and the countries' GDP. In general, studies have shown the negative effects of the contamination by pesticides on bees; however, most publications are with bees of the Apis genus, and therefore it is necessary to explore the action of pesticides on bumble bees and wild bees, as well furthur as studies are needed regarding the sublethal effects of these products on bees as the number of molecules used in the management of agricultural crops is vast. [ABSTRACT FROM AUTHOR]