The walkingstick is a defoliator of broadleaved trees in North America.
The black oaks, basswood, and wild cherry are the most common preferred
hosts but numerous other hardwood species are attacked. This insect is
widely distributed over the United States east of the Rocky Mountains as
well as Manitoba and Ontario in Canada. At times, populations build in
sufficient numbers to defoliate trees over large areas.
[Illustration: Male walkingsticks feeding on oak.]
These slender, wingless, stick-like insects are pale green when young,
but gradually change to a dark green, gray, or brown at maturity. The
adult female measures up to three inches in length and is more
stout-bodied than the male. Mating usually takes place in August and egg
laying begins six to ten days later. The eggs are dropped to the ground
where they overwinter in the leaf litter. In the northern part of the
walkingstick’s range the eggs take two years to hatch. In the South,
walkingstick eggs hatch the summer after they are laid, usually starting
in mid-May. The newly hatched walkingstick looks like a miniature adult.
Parasitic wasps and flies are active against the immature walkingsticks
but are not efficient enough to cause a substantial population
reduction. Flocks of robins, blackbirds, and grackles have a much
greater impact, however. The defoliation caused by walkingsticks
generally occurs on upland sites in stands which are not of high value
or intensively managed. For this reason there has been little interest
in control.