An interesting behavior of several unrelated bees is to live underground in burrows and tunnels. Some of these, such as bumble bees, nest in pre-existing cavities made by rodents or small mammals. Others, like the ones discussed below, dig their own tunnels as a shelter for their offspring.
The group name "mining bee" is applied to the members of at least two different families -- the halictid and andrenid bees. The females in these families dig 1/4 to 1/2 inch diameter, cylindrical tunnels in shady areas where vegetation is sparse and the soil is loose. The females construct chambers at the end of the tunnel and provision them with nectar and pollen, the food of the offspring. Sweat bees are a familiar member of the "mining bee" group. Other members are similar in appearance, though slightly larger.
In most situations it will not be necessary to eliminate ground-nesting bees. If the insects can be ignored and their tunnels tolerated, do so. However, if the slight threat of being stung justifies control (as on playgrounds or in oft-tended flower beds) a simple control procedure is available. The recommended treatment for ground-nesting bees (and wasps) is to wait until evening and dust the tunnel and surrounding area with Sevin dust. Other lawn or garden insecticide sprays can also be used, but dusts have the advantage of not soaking into the soil. Repeat treatments may be needed. If you wish, the tunnels can be covered with a shovelful of dirt.
This article originally appeared in the May 11, 1994 issue, p. 67.