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Patrick Porter
Integrated Pest Management Specialist
WVU Extension Service
West Virginia has had an extremely cold Spring, and this has hampered our first attempt to propagate hornfaced bees for orchard pollination. Adult bees were reared in paper tubes by Dr. Suzanne Batra in Maryland and shipped to West Virginia in February. Some of the tubes were placed outdoors in early April in a blueberry orchard with apple trees nearby. Other bees were placed on a wooded farm with many nearby weed species. Bee housing is illustrated in figure 1.
Hornfaced bee paper tubes inside a protected PVC shell
After unusually warm weather in late March, a hard freeze (16 degrees F) set in on April 10, and temperatures have remained approximately 10 degrees below normal since that time. Many early pollen sources were killed by the April 10 freeze, and subsequent freezes eliminated pollen sources as well. Hornfaced bees were flying before the April 10 freeze and could be seen flying after the freeze. Populations are currently weak, and we have accepted a shipment of bees from Hampshire County High School in Romney, West Virginia to supplement our colonies. The high school bee population was kept in cold storage until May 20 to hedge against the cold weather and its effects on pollen sources.
Two observations may be of value to other beekeepers. Limited experience suggests that bee mortality was extremely high in plastic-coated paper tubes as compared with paper tubes that were not plastic-coated. Dissection of plastic-coated tubes revealed many dead pupae and an abundance of mold. Similar pupae and mold were rare in paper tubes not coated in plastic.
The hard freeze on April 10 and other freezes thereafter did not appear to kill bees, but effectively eliminated all pollen sources for about 10 days. Flowers that were in bloom were killed, and flowers nearing bloom were either killed or severely damaged. Because the adult bees originally came from eastern Maryland, we believe they may have been further along in the developmental process than local West Virginia bees would have been. It is possible that locally-reared bees would not have been flying until after the period of extreme cold.
Future updates will be posted on this Web site.