Summary

The project will investigate the effects of three commonly used active ingredients in fungicidal sprays during flowering of almond and canola on the health of honey bee brood. The active ingredients tested will be selected from those most commonly used by the industries, and most likely include iprodione and chlorothalonil. A third active ingredient may be flutriafol, as it is a relatively new ingredient with moderate acute oral toxicity to honey bees. The final choice of active ingredient (a.i.) to be used in feeding trials will be based on the outcome of the literature review and an inquiry among growers of pollination dependent crops.
To investigate known effects of fungicides on the health of adult workers, nurse bees, brood, overall hive performance and on native bees, we will do an exhaustive and critical literature search and use this information to produce a literature review, which will be submitted to an international peer reviewed journal.
For at least three commonly used active ingredients (possibly chlorothalonil, iprodione and flutriafol), the impact of its presence in pollen will be assessed for (a) survival of nurse bees, and (b) their hypopharyngeal gland development. This will be done using feeding experiments of newly eclosed bees in small cages. For the ingredients that show significant impact on nurse bees or their hypopharyngeal gland development, the effects on larval development will be investigated using whole hive feeding experiments (following Zaluski et al 2017).
Care will be taken to use realistic concentrations of the a.i., this will be achieved by harvesting the pollen brought back to the hive after spraying in five orchards and (a) using this pollen directly in the small cage feeding trials; and (b) quantifying the amount of a.i. in the pollen. These concentrations will be used in the hive feeding trials.

Program

Honey Bee

Research Organisation

The University of Adelaide

Objective Summary

The project has five main objectives:
(a) Produce an in-depth literature review of the effects of the active ingredients commonly used in fungicidal sprays on hive health and native bees, to explore known effects and knowledge gaps;
(b) Quantify the amount of a.i. in pollen brought back to the hive within 24 hours after spraying;
(c) Experimentally establish the effects of commonly used fungicidal sprays on survival of nurse bees, and their hypopharyngeal gland development through caged experiments;
(d) For those a.i. that prove harmful to nurse bees, investigate the impact on brood development using whole hive trials; and
(e) Present these results in international, peer reviewed journals.