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ARS Home » Pacific West Area » Logan, Utah » Pollinating Insect-Biology, Management, Systematics Research » Research » Research Project #443616

Research Project: Optimizing Pollination of Blueberries, Strawberries, Raspberries, and Other Specialty Fruit Crops in Utah

Location: Pollinating Insect-Biology, Management, Systematics Research

Project Number: 2080-21000-019-061-A
Project Type: Cooperative Agreement

Start Date: Dec 1, 2022
End Date: Jul 31, 2025

Objective 1 Document the wild bee community visiting flowers of small fruits (blueberries, strawberries, currants, and raspberries) Objective 2 Test different ‘bee condo’ rearing materials to determine the best condo design to deploy for each Osmia species. Objective 3 Use behavioral observations and pollen identification from Osmia lignaria, O. ribifloris, and O. bruneri nests to determine crop visitation rates, pollen preferences, and nesting rates of the bees. Objective 4 Test different stocking densities of the three Osmia species and measure the reciprocal crop yields Objective 5 Provide recommendations to Utah small fruit growers, and other growers of these crops, on the use of Integrated Crop Pollination practices—such as the use of alternative managed pollinators Osmia lignaria, O. ribifloris, and O. bruneri.

Small fruit crops such as blueberries, strawberries, currants, and raspberries 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. We will document the bee community visiting these crops to determine the primary 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 (USDA PIRU, K. Graham) and specimens held at the U.S. National Pollinating Insects Collection (Logan, UT). We will also test stocking densities, behavior, and predilections of three managed solitary bees native to Utah, Osmia lignaria, the blue orchard bee, O. ribifloris, and O. bruneri. To determine the efficacy of O. lignaria, O. ribifloris and O. bruneri for these crops, we will release adults of both species during bloom and place nesting condos throughout the crop field. We will also test nesting rates in different condo substrates to optimize the condos used for each species. Visitation to crop flowers will be monitored through observations in the field, and through the comparison of pollens found in completed bee nests to pollens extracted from crop flowers. Pollen identification allows us to determine plant preferences for these species, thus informing its usefulness as a managed pollinator for each crop. 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 of crop). Stocking densities will be tested through use of large insect cages, which allow us to vary bee densities during bloom and measure crop yields in relation to stocking densities.