Garden Column for the Salisbury Post
Darrell Blackwelder
March 21, 2002
 

 A few homeowners have called this past week complaining
about hundreds of bees hovering over their lawns. Many are
concerned about this unusual phenomenon, especially this early
into the spring.
 One homeowner reported that literally hundreds of small
black bees were swarming low to the ground in a barren area
digging holes and making red clay mounds of soil. The primary
concern was that the bees were going to kill the grass did these
bees sting since the residents were allergic to bee stings.
     As it turns out, the bees hovering around the clay soil are
a type of solitary digger bee. These bees are tunnel into the
clay soil to lay eggs.  The look very similar to honey bees
ranging from 1/2  to 3/4 inches long and  may be a variety of
colors such as blue, black, copper colored or metallic brown.
Other solitary bees are mason and sweat bees.
 
     Solitary bees are primitive without the social order honey
bees, yellow jackets or hornets.  They have no cast system such
as honey bees with a queen and worker bees.  They live by
themselves, boring holes into the soil to lay eggs in individual
tunnels. The bees often line the burrow with a water proofing
secretion to protect the eggs from moisture. Ground­nesting bees
generally prefer nesting in areas with morning sun exposure and
well­drained soils containing little organic matter. Burrows are
excavated in areas of bare ground or sparse vegetation. These
bees usually avoid damp soils.
  A huge congregation of solitary bees boring into the ground is
quite a curiosity.  Large areas of soil are mounded into multiple
rows of 6 inch deep holes. Borrowing bees do not kill well
established lawns.
     Female bees collect pollen and nectar and making a round
ball about 1/4 long on the side of the cell wall. Even though the
bee collects both honey and pollen, it does not make honey as its
cousin the honey bee.  An egg is placed on the pollen and nectar
ball providing food for the newly hatching larvae.
     Solitary bees are excellent pollinators.  These bees play a
vital role in pollinating of crops and wild plants. With all the
problems domesticated bees are having with mites and other
diseases, man can use all the help he can get from these docile
insects.
     These bees are not aggressive and they rarely sting.  Avoid
the nesting area 4­6 six weeks if possible. Once the nesting is
complete, the insects leave and continue pollinating.
     Bees usually bore in areas that are weak or thin.  Healthy
vigorous growth is natural method of controlling the insect.
 Cultural control methods include heavy watering or
irrigation with a lawn sprinkler now during the nest­building
period to discourage nesting. If the soil or location is not
conducive to a healthy lawn, using ground covers or heavy mulches
may be an alternative solution. Mulches may be used on bare
patches caused by heavy traffic where grass will not grow.
  If all else fails Sevin 50% wettable powder or the liquid
formulation easily kills the insect.
 

     Darrell Blackwelder is an agricultural agent in charge of
horticulture with the North Carolina Cooperative Extension
Service in Rowan County. For archived garden columns or other
information visit the Master Gardener Website at web site at
www.rowanmastergardener.com