ORNAMENTALSAND
TURF
ORNAMENTALS
The information and recommendations in this newsletter are applicable to North Carolina and may not apply in other areas.
Scoliid wasps are dark in color, relatively large, robust, slightly
hairy insects with light yellow spots or other markings. The most
common scoliid wasp in North Carolina is Scolia dubia, sometimes
called the bluewinged wasp. Bluewinged wasps are black with a
metallic blue highlights on the wings and thorax. The abdomen has
two yellow spots near the middle and the tip is reddish brown.
Scoliid wasps are usually considered beneficial insects because
they help control green June beetle and other grubs. They are
present in North Carolina from June to October; however, they are
most abundant during the month of August. The wasps are often seen
hovering a few inches above lawns in search of grubs, flying in
loops and figure eight patterns. The female wasp digs through the
soil in search of the grubs, burrowing her own tunnels or following
those made by the grubs. On locating a grub, she stings and
paralyzes it. After laying her egg, the hatched wasp larva
consumes the grub alive. Sometimes these wasps are quite abundant
and conspicuous as they swarm during their mating dances. Later,
females spend more time digging for grubs and the swarms are not as
noticeable. These wasps forage for nectar and sometimes sleep on
plants. As the nights cool, they burrow under the soil at night.
Scoliids do not have any nest-guarding instinct and rarely, if
ever, sting humans. Thus, no control measures are suggested.
Elm is the major host for larger elm leaf beetles, but the beetles
will also feed on dogwood, hazelnut, pecan, river birch, plum, and
hawthorn. The larger elm leaf beetle often suddenly appears in
great numbers, does tremendous defoliation for a year or two, and
then disappears for an indefinite time (perhaps decades). It is
more damaging for an elm to be defoliated in the spring than later
in the summer or fall, so present damage is probably of little
consequence to the health of these trees. Sometimes groups of
larvae can be see on the soil surface beneath a tree. The beetles
overwinter as grubs in the soil. They pupate in the spring, and
the new adults emerge in May. Adult larger elm leaf beetles chew
holes in the leaves and lay their eggs on the leaves. The larvae
hatch and skeletonize the leaves as they feed. There is one
generation of these insects per year. Adults may survive
throughout the summer. This insect can be controlled with Orthene,
diazinon, Sevin and other pesticides.
Web page last updated on September 3, 1996 by Stephen J. Toth, Jr..
