Project Overview

Reports

Commodities

• Animals: bees

• Fruits: berries (blueberries)

• Pollinators: honey bees,

Target Pests

Practices

• Pest Management: pesticide application timing

• Crop Production: pollination/pollinator health/habitat

• Natural Resources/Environment: biodiversity, wildlife

Commercial highbush blueberry (Vaccinium corymbosum L.) production is highly reliant on insect pollination for berry set. Effective pollination during a small window of bloom can be the difference between a high-yielding successful harvest and economic losses. Blueberry production is a growing industry in Florida with a 65% increase in acreage in recent years. Due to the early bloom time and limited wild pollinator populations, Florida blueberry growers rely almost exclusively on managed honey bees for pollination. Many of them have reported poor pollination in recent years, and recent research has shown that blueberry production is limited by pollination. Improved pollination can be achieved by increasing the stocking density of honey bees and/or improving the efficacy of existing pollinators. However, pollination is not the only factor that blueberry farmers must consider when making management decisions.

While pollination is a crucial component of blueberry farm management, sufficient pest management is also essential for profitable yields. Several damaging insect pests require frequent prophylactic insecticide applications, some of which are applied during the pollination period. Research has shown that insecticides can have both lethal and non-lethal effects on pollinators including reduced bee foraging rates, changes in bee behavior, and reduced bee body size and reproductive ability. Limited research also shows that insecticides applied during bloom can repel pollinators from visiting crop flowers. However, no research has been done to examine these effects in southern highbush blueberry systems. Effects of insecticides on pollinator behavior, including repellency, changes in their foraging rates, or changes in their interactions with flowers, could have a devastating impact on blueberry pollination leading to low yields.

In order to address this knowledge gap, our proposed study will examine the effects of insecticides used during blueberry bloom on both pollinator visitation rates and pollinator behavior. Our goal is to quantify the magnitude and duration of any non-lethal impacts on pollinators caused by commonly-used insecticides, develop recommendations for pollinator-friendly insecticides and insecticide application strategies, and enhance both pollination and yields of blueberries in Florida through improving the efficacy of pollinators. In order to achieve our goals, we will conduct two experiments. First, we will assess pollinator visitation rates and behavior on ten blueberry farms. For each farm, we will measure pollinator activity preceding and following a farmer’s typical insecticide applications. The wide range of insecticides used across farms will allow for a broad spectrum of chemicals to be assessed. We will also correlate overall pollinator activity throughout bloom with a toxicity score derived from farmer spray records and calculated specifically for toxicity to bees. Secondly, we will conduct a controlled experiment on a UF research farm with four commonly used insecticides and a control. For each treatment, we will examine potential non-lethal effects on pollinators including repellency and changes in flower-visiting behavior. Data will be collected over the course of ten days post-application to allow for the duration of the effects to be assessed. Results from this research will be communicated to farmers through field days and workshops, extension publications, and online materials including a video tutorial and blog posts.

This proposed project will enhance our understanding of non-lethal impacts of commonly used insecticides on blueberry pollinators. When paired with current knowledge on insecticide efficacy, we will be able to provide better insecticide recommendations specifically for the bloom period. These recommendations will sustainably integrate pest and pollinator management to improve yields; farmers will be able to use necessary insecticides to manage pests without fear of repelling pollinators and reducing pollination. In the absence of repellent insecticides, we expect that pollinator efficacy will improve resulting in a greater return on investment from pollinator-related expenses.