Matthew Stevens: Nesting bees are important pollinators and aren't aggressive

Though I normally write about plants, there are many insects we encounter as we are outside gardening. Some can be problematic for our plants, but most are non-pests and many are beneficial.

Everyone knows about honey bees, but less well understood are ground nesting bees such as miner bees. Miner bees are active for a few weeks in early spring and are out and about now.

Miner bees live in the ground, particularly in areas with dense soil and sparse vegetation. Unlike honey bees, they do not all nest together in a single hive, but rather each bee will create its own individual tunnel in the ground. Thus, a yard that has miner bees present may have hundreds of small holes in the soil in relatively close proximity.

When the bees hover above their nests in the day, the sight of so many bees flying around in the yard at ankle or knee high can be a bit intimidating.

Miner bees, however, are not aggressive and very rarely sting. The ones that you see flying are generally males and do not have stingers. The females can sting, but they dig the holes in the ground and raise the young so they rarely leave the ground.

You can walk through a group or even mow over them without fear of being stung, though on rare occasions if a female becomes trapped inside your clothing they may eventually sting.

As honey bee populations decline, the importance of miner bees and other native bee species is increasing, because, though they do not produce honey, they are important pollinators. Miner bees are known to frequent many ornamental and edible flowering plants. Other solitary ground nesting bees, such as mason bees, and digger bees, also play an important role as pollinators and lack aggressive characteristics.

Because of their role as pollinators and their lack of aggression, we do not generally recommend any chemical treatment or control measures for miner bees and other solitary nesting types, despite the fact that they can be a slight nuisance for a few weeks each spring if nesting in an undesirable location.

If you simply can’t stand them, they do not like to nest in wet soils, so heavily watering the area may drive them to nest somewhere else without killing them. Once you’ve successfully relocated them, reseeding the area with grass may prevent them from returning next year.

Of course, there are other some types of flying insects that nest in the ground that are aggressive. The most common of these is yellowjackets, which is actually a wasp.

Yellowjackets do have some value as pollinators, but they are aggressive and nest in groups. If you should step on, mow over, or otherwise encounter a yellow jacket nest in the ground, you might be in for some trouble.

If you find one of these nests, the best way to treat it is to spray into the nest in late afternoon or early evening with a hornet and wasp spray. Most of the colony will be inside the nest at this time of day, so a good strong spray will likely eliminate them.