Honeybees (Apis mellifera Linnaeus) (Hymenoptera: Apidae) play a major role in the pollination of cranberry (Vaccinium macrocarpon; Ericaceae). However, fungicide applications during cranberry bloom may affect bees foraging behavior. This research reports the amount of cranberry and noncranberry pollen brought back to hives immediately before and after two types of fungicide applications. The amount of cranberry pollen decreased while the amount of noncranberry pollen increased following a fungicide application. However, this relationship differed depending on the type of fungicide applied. Understanding how different fungicides specifically impact bee behavior is essential to minimizing bee exposure to potentially harmful chemicals.

Social wasps can be serious pests in fruit growing plantings and are becoming increasingly problematic for grape growers. In this study, we conducted two experiments to assess the species composition and seasonal phenology of social wasps in Wisconsin vineyards in 2015 and 2017. In 2015, three attractants were used: (1) wine; (2) heptyl butyrate (HB); and (3) acetic acid and isobutanol (AAIB) and in 2017, two attractants were used: HB and AAIB. In both years, the same eight species were trapped from the genera Vespula, Dolichovespula, and Polistes. The predominant wasp species trapped were Vespula maculifrons, Vespula vidua, Vespula flavopilosa, and Vespula germanica in 2015 and V. maculifrons, V. flavopilosa, V. germanica, and Dolichovespula maculata in 2017, in order of total abundance. The populations of V. vidua decreased in 2017 compared to 2015, indicating large inter-annual variation. In both years, AAIB lures trapped significantly more V. flavopilosa, V. maculifrons, and V. germanica, the three most prevalent species during grape harvest, than HB, whereas HB lures trapped more V. vidua than AAIB. Wine was generally attractive to all species in 2015. This study identifies for the first time the wasp species present in Wisconsin commercial vineyards using chemical attractants. This knowledge, along with the seasonal phenology of these pest species, will help facilitate the development of management strategies for social wasps in commercial vineyards.

Most cranberry (Vaccinium macrocarpon) growers rent honey bees (Apis spp.) to insure proper pollination of their crop. However, honey bees are not the most efficient pollinators of cranberry and there have been increasing efforts to improve the pollination services provided by honey bees. Cranberry flowers provide small amounts of nectar and this research project tested whether supplementing hives with various sugar sources could increase the amount of cranberry pollen foraged. High fructose corn syrup, honey, and sucrose did not increase the amount of cranberry pollen, or the percent of cranberry pollen, foraged and returned to the hive. However, overall weights of the pollen samples were significantly higher for hives treated with high fructose corn syrup and sucrose compared to hives supplied with honey, water, or no additional solutions. Although not explicitly tested in this study, these results suggest that honey bees are incorporating these carbohydrates into their pollen bundles. However, since the supplemental sugar feedings did not increase the amount, or percentage, of cranberry pollen grains foraged, there is limited evidence that supplemental sugar feedings will improve honey bee pollination services in cranberry. Future work in this area should examine the relationships between pollen quality and supplemental sugar feedings, as these feeding may improve hive health in crops with poorer quality floral resources.