Non Technical Summary
Blueberry is a significant specialty crop grown across the United States that supports healthy human diets and farm communities, including growers and beekeepers. Pollination is a critical component of successful and profitable blueberry production, and although there have been major advances in breeding, horticultural practices, and pest management for this crop, extension recommendations for pollination have not changed in decades. Spring weather variability challenges growers' ability to appropriately adjust their bee stocking, and there is little research-based guidance on how to adapt pollination strategies for specific cultivars, weather conditions, or farm situations. This project will respond to stakeholder priorities to provide modern pollination-related decision support tools and recommendations, by combining expertise from applied entomology, apiculture, horticulture, breeding, economics, and meterology disciplines working with growers across four key blueberry-producing states. Our team will develop new research and extension outputs that enable growers to tailor their pollination practices for greater return on investment. Specifically, we will compare and conduct cost-benefit analyses of different strategies for honey bee pollination; determine pollination requirements and pollinator attraction across new and existing cultivars; determine how variable weather conditions affect blueberry pollination; develop predictive models of pollination, fruit set, and yield for development of a Pollination Planner; and deliver information on improved blueberry pollination to the industry.
Animal Health Component
Research Effort Categories
Goals / Objectives
1. Conduct cost-benefit analyses of different honey bee stocking density and placement strategies to develop recommendations for modern blueberry systems.2. Determine pollination requirements and pollinator attraction across new and existing cultivars.3. Determine how variable weather conditions affect blueberry pollination.4. Develop predictive models of pollination, fruit set, and yield for creation of a Pollination Planner to improve pollination management decisions.5. Deliver information on improved blueberry pollination to the industry.
1a. Comparing stocking density. We will compare yields of commercial blueberry cultivars between existing standard colony densities (two colonies/acre in MI and three colonies/acre in FL) and double the density currently used(4 colonies/acre in MI and 6 colonies/acre in FL).Using six replicated ~40 acre farms for each stocking level in MI and FL, we will measure bee activity on flowers and overall fruit set using the methods described below to determine whether increased honey bee stocking densities results in increased yields.During two-three weeks of peak bloom for each cultivar, when it is sunny, air temperature exceeds 60oF, and wind speed is below 5 mph (Clark & Robert 2018), we will record the number of bees visiting blueberry flowers at the farms with high and low stocking densities.1b. Comparing colony placement. In each cooperating state, we will monitor crop pollination and honey bee colony health in fields with colonies placed in larger clusters away from production areas to reduce pesticide exposure and improve placement efficiency, compared to placement throughout the production area (the current standard).1c. Economic analysis. For the baseline scenario of the economic analysis, we will utilize the enterprise budgets generated for blueberry production in WA, OR,FL,and MI. The baseline scenario will have the existing standard colony density for blueberry production in the three regions (4 states). We will estimate the costs and benefits of the alternative practices (i.e., increasing honey bee hive stocking densities and hive placmenet) and compare these figures with the baseline using partial budget analysis.Using results of the partial budget analysis, we will calculate and compare break-even points for the baseline and alternative scenarios.The break-even point will serve as the threshold after which an economic loss occurs. In addition, we will undertake risk analysis by examining the sensitivity of profit uncertainty in critical economic parameters (e.g., crop yield, output price, pollination cost). We will also use the information gathered in this objective to determine how many pounds of blueberries each honey bee colony supports, resulting in a metric that can be compared among cultivars and regions.Objective 2. Five leading cultivars and five promising new cultivars were selected from each growing region, representing a large variation in genotypes used in current breeding programs (Table 1). Cultivars were selected with input from experts in highbush blueberry breeding.These cultivars will be tested to determine their inherent needs for pollination and their response to pollination treatments in the greenhouse and field.2a. Comparing pollination requirements among cultivars. To determine the level of auto-fertility and self-compatibility of these cultivars, 5 plants of each cultivar will be grown under optimal conditions in a greenhouse. During the flowering period, three flower clusters on each plant will be assigned to one of the following treatments: 1) no pollination, 2) self-pollination, and 3) cross-pollination. Pollination will be achieved using a fine paint brush to apply pollen collected from the same cultivar (self-pollination) or from a different cultivar with distinct parentage that blooms at the same time (cross-pollination).2b. Determine how flower traits vary among cultivars, and implications for pollination. Using the same cultivars we evaluate in the field as described above, we will additionally measure the physical and chemical traits of flowers. Bee visitation rates will be measured for each cultivar at each site, using timed observations conducted on three separate dates during the bloom period for each cultivar.Objective 3.We will complete three sub-objectives: 1) Determine bloom phenology based on accumulation of growing degree units (e.g., days); 2) Understand how environmental conditions influence honey bee activity across the important production regions included in this study; and 3) Determine how a range of temperature and humidity conditions affect blueberry pollination. Field, growth chamber, and lab work will be done in 2021 and2022, with resultant data being used for constructing and validating the Pollination Planner tool in 2023-2024.Objective 4. Develop predictive models of pollination, fruit set, and yield for creation of a Pollination Planner to improve pollination management decisions. We will coordinate the information gathered in Objectives 1-3 to develop and validate regionally-relevant and cultivar sensitive models for blueberry pollination, fruit set, and yields, which will then drive our Pollination Planner. This will be based on user-inputs on cultivar, stocking density, price per colony, and price per pound. The system will use the data gathered in this project and in previous research to include how relative pollination and yield is impacted by regional weather variables across cultivars. The tool will also show how relative profit levels vary based on stocking density and berry prices, further supporting pollination decisions.5. Deliver information on improved blueberry pollination to the industry. We propose toconnect and engage blueberry grower, beekeeper, and crop consultant networks by: 1) includingadvisory board members, innovative growers, beekeepers,and crop consultantsintheinitial stages of developing the Pollination Planner;2) building a broader network of growers, beekeepers, and crop consultants through the frequent release of multimedia (video, podcast, infographic) content through social media networksand online resources (e.g., project website and Pollination Planner tool); 3) surveying our network to determine current practices and understanding around blueberry pollination and how these change as a result of our project; and 4) hands-on field day workshop and training activities combined with printed Extension products to support growers and crop consultants in their use of the Pollination Planner. The surveys will be conducted at the start and the end of the project to provide Impact Assessment, and this will be led by co-PD Suzette Galanito, who has experience developing surveys for fruit growers, gaining Institutional Review Board approval, etc. (see Obj. 5b). This project we will create a range of Extension and outreach products to extend the information beyond the project team and the cooperating states. This information will be delivered to growers, beekeepers, and Extension professionals through workshops, existing university websites (MSU pollination site, MSU Blueberry Team, UF Blueberry Extension, Oregon Bee Project/OSU Pollinator Extension, WSU Small Fruits), and our regional Extension networks. Our materials will also be highlighted in the Small Fruit Update a newsletter that is based in the PNW but whose reach extends across the nation. This highly professional and timely newsletter is read by hundreds of growers and other industry professionals each time it is released by email. Additionally, the team in Oregon on this project are subcontracting the on-farm activities in that state to a field research team that work closely with the Small Fruit Update group, helping to ensure a close connection between the research and education.?