Project Number: 2080-21000-019-060-R
Project Type: Reimbursable Cooperative Agreement
Start Date: Oct 1, 2022
End Date: Sep 29, 2025
Small fruit crops such as blueberries, strawberries, and currants greatly benefit from animal-mediated pollination. However, the pollination needs of these crops in Utah are understudied. Additionally, the reliance on honey bees alone for crop pollination can result in low yields due to a mismatch in pollinator efficacy (honey bees are not always the best pollinator for some crops) or poor health of honey bee hives. Contracting with commercial beekeepers can also result in substantial production costs for growers. Therefore, we will investigate two important components of an Integrated Crop Pollination system for these crops in Utah, including promoting pollination from wild bees, and use of alternative managed pollinators. With this integrated approach, growers can decrease pollination costs and increase yields.
Objective 1: Document the wild bee community visiting flowers of small fruits (blueberries, strawberries, and currants). Objective 2: Use behavioral observations and pollen identification from Osmia lignaria and O. ribifloris nests to determine crop visitation rates and pollen preferences. Objective 3: Test different stocking densities of Osmia lignaria and O. ribifloris, and measure the reciprocal crop yields. Objective 4: Provide recommendations to Utah small fruit growers, and other growers of these crops, on the use of Integrated Crop Pollination practices—such as the alternative managed pollinators Osmia lignaria and O. ribifloris. The bee community visiting these crops will be documented to determine the primary pollinators. Understanding which bees are the primary pollinators will help inform best management practices to support local bee communities, in turn providing a more abundant supply of pollinators. We will document the bee community by doing timed observations at crop flowers to estimate relative abundances of groups of bees, followed by timed sampling (netting) of bees at flowers to identify bees to species. Bees will be identified at the USDA ARS Pollinating Insects Research Unit (K. Graham). We will also test stocking densities, behavior, and predilections of two managed solitary bees, Osmia lignaria, the blue orchard bee, and O. ribifloris, the blueberry mason bee. Osmia lignaria has been widely established as a beneficial pollinator of several specialty crops, including cherries, apples and pears. More work needs to be done to determine its efficacy at pollinating other fruit crops, though there is some evidence of its usefulness in almond and blueberry pollination. Osmia ribifloris is a promising new managed solitary bee. This native Utah bee is being used in blueberry cropping systems as a supplemental or alternative managed pollinator, but its use is relatively new and widely unknown. Osmia ribifloris is known to have high rates of fidelity to blueberry flowers, and management techniques for its use in blueberry pollination have been developed by NativeBees. Although Osmia ribifloris visits additional flowers beyond blueberry (polylectic), it shows intense predilections for certain flowers, such as blueberries and currants. To determine the efficacy of O. lignaria and O. ribifloris for these crops, we will release adults of both species during bloom and place nesting condos throughout the crop field. Visitation to crop flowers will be monitored through observations in the field, and through the comparison of pollens in nests. Pollen identification allows us to determine plant preferences, thus informing the usefulness of these bees as managed pollinators. For crops where these bees show particular promise as managed pollinators, we will then evaluate stocking densities (how many adult males and females are released per acre) and associated crop yields.