insects lay they eggs inside the stems of trees they girdle twigs, and
effectively cutting them of the trees water and nutrient supply. This causes twigs to wither, turn brown and
drop. Because there is little that can
be done to effectively manage these pests, it is important to learn their
life cycles so that you can effectively explain these problems to your
periodical cicadas Tibicen spp, and Magicada spp.
Family: Homoptera: Cicadidae
|Host Plants: Many
Diagnosis: When adults lay enough
eggs in twigs they can kill them. This
is primarily a problem on new nursery stock, and when large numbers of
periodical cicadas emerge. Damaged
twigs and branches have a series of slits where females have laid their
eggs. Damage from the periodical
cicada is most severe near mature stand of trees where cicadas can complete
their long life cycle. Adult periodical cicadas have orange wings with black
bodies and red legs. In contrast
damage from the annual or dog day cicada is minimal.
|Biology: Nymphs of all cicadas feed on roots of
trees. Nymphs of annual cicadas feed
on roots from 2-5 years and those of periodical cicadas feed on roots for 13
or 17 years before they become adults.
Adult annual cicadas are present from mid-July to late summer. After adult periodical cicadas emerge in
late May or early June, they fly for 6 weeks.
Male cicadas produce a shrill call that is quite distinctive. When they emerge by the thousand, the
shrill call of the males to their mates is both distinctive and overwhelming. During the adult flight period adults mate
and females lay egg in twigs. Several
weeks after eggs are laid a nymph hatches, feeds and drops to the ground to
dig for tree roots where they suck on plant sap. Damage associated with root feeding has not
been measured and is assumed to be minimal.
|Control: Field trials with applications of broad
spectrum insecticides show that none can effectively reduce injury from the
periodical cicada. Contact your local
Extension service to find out when and if periodical is expected in your
area. Discussing the issue with your
clients before trees are
covered with cicadas will help you better manage the situation.