Peter T. Hertl and Rick L. Brandenburg
March and April are the typical months to notice the activity of ground-nesting bees in turf. Activity has already been reported this year, despite the cool weather, and will likely increase in the coming weeks. These bees form a small mound of soil with a pencil-sized entrance hole. Each bee nests singly, but they often are found in groups where the turf is thin. Colony-type nesting areas are often located on south facing slopes, but can also occur in flat areas.
These bees generally don’t sting and pose little danger to people. Both the mounds and bees will disappear within a few weeks, and normally do not require control with insecticides. Nonchemical deterrents include heavy watering, or tilling and heavy mulch in landscape beds.
For more information on ground-nesting bees, please see the Turffiles publication, Bees in Turf : http://www.turffiles.ncsu.edu/articles/tf0055.aspx