Digger wasps are continuing to multiply in numbers in the
Lowcountry. At Possum’s we use to get a few complaints in localized areas, now
the numbers seem to be on the rise. One faithful reader of the ‘Horticulture
Hotline’ sent me a 14 page letter describing the progression of damage to her
yard. I saw an old friend in the grocery store and a conversation that would
have dominated by fishing stories or stories about old times was dominated by ground bees.
The presence of wasps is intimidating and unsafe.
Digger wasps start out as just a few holes in the yard. The
holes are where the adults lay their eggs. In the spring, the young emerge. In
the fall these wasps are now adults and they dig new holes and lay eggs for the
following spring. In a very short time period, you can go from having a few
digger wasps to thousands. All these holes can ruin your turf areas and the
wasps make it less enjoyable to be in the yard.
Most of these wasps are predatory feeders. They eat grubs
(should manage for moles and potential turf damage), small flying insects and
ground dwelling insects (mole crickets, etc). The wasps sting the prey to
death, then bring the dead prey back to the wasp’s hole (nest), then lay an egg
on it so the young has an instant food supply when it hatches.
All control should be done at dust or at night when the
wasps are in their hole. You need to plan on several applications of products
to manage this pest. Since the wasps eat insects in your yard that you should
be managing to certain thresholds, going after the wasp as well as their food
source should benefit you greatly. Since the wasps like subsurface insects,
Sevin would be a good product to start your management program.
If you just have a few holes, Delta Dust is a great product.
At night treat in and around the hole. Some people will also “plug” the hole.
At Possum’s we sell the plugs, but you could possibly use something from around
the house. Be sure to turn off the irrigation and check for rain.
If you have many of these uninvited guests, DeltaGard G or
Turf Ranger could be used across the whole area. Remember they fly, so getting
your neighbors involved is crucial. These products need to be watered in to get
to the target. Turf Ranger recommends ½ inch of water. Water the product in
slowly so the product soaks into the ground, and does not run off into a
non-target area. Apply these products when you first see the wasps and until
they are gone, waiting at least one week between applications.
EcoVia is a National Organics Program compliant product that
is labeled for wasps and other small flying insects (mosquitoes – yeah). EcoVia
is safe to use around water, kids, and pets. Consider using EcoVia in your
product rotation.
When treating always wear dark clothes and have a can of
wasp freeze on your person. Digger wasps did not get there overnight, and they
are not going to go away overnight.
