1a. Objectives (from AD-416):
Evaluate the use of blue orchard bees combined with honey bees as pollinators of almonds in California to provide an alternative strategy to using only honey bees as pollinators by determining 1) sustainability of blue orchard bee populations in an orchard system, 2) whether nut yields are equivalent between the new and standard pollinator strategies, and 3) if the new strategy is economically viable. Also, determine if providing non-crop floral resources that bloom before, during, and after almonds will 1) enhance blue orchard bee reproduction 2) distract bees from pollinating the target crop, and 3) be cost effective and management friendly.
1b. Approach (from AD-416):
In the first two years of this project, blue orchard bees along with their nesting materials will be deployed in at least 40 acres of three almond orchard sections along with honey bees at recommended rates such that a full complement of pollinators is applied. The reproductive output of the blue orchard bees will be determined (number of cells and sex ratio) once the bees have matured in the new nests. Nut yield also will be evaluated according to proximity to nesting blue orchard bees and to honey bee hive locations. For comparison, nut yield also will be assessed in three matching sections of other almond orchards that used only honey bees as pollinators. The economic inputs into each pollination management system will be recorded throughout the year to assess costs to the almond producer. In years 3&4, blue orchard bees plus honey bees will be used as above in six orchards. In three of the orchards, spring-flowering plants will have been established for use by the bees as extra resources. Blue orchard bee reproduction and nut yield will be assessed according to proximity to the floral resources to determine any effects of the resources on bee and nut yields. In the year 5, a demonstration of best practices using an alternative strategy will be performed in at least one orchard to share with the almond and bee industries.
3. Progress Report:
We initiated the study of pollination of almond orchards with (n = 6) or without (n = 6) Osmia lignaria in the presence of Apis mellifera (honey bees). All experiments were performed as prescribed, and data on bee reproduction and nut yield are being collected. Bees needed for continuation of this multiyear project are being managed in a temperature controlled storage facility.