Agriculture Reference
In-Depth Information
Leafhoppers
Several species of leafhoppers, including potato leafhopper, rose leafhopper,
and white apple leafhopper, attack pome and stone fruit crops. Leafhoppers
are small, wedge-shaped insects about
⁄
8
inch long with sweptback wings.
1
They have sucking mouthparts like aphids but are much more mobile. Al-
though they feed only on the leaves, they damage fruit by depositing their
feces on them. These deposits create spots on the fruit resembling tobacco
juice and support the growth of sooty mold. A far more serious impact is
that some leafhoppers vector plant diseases such as fire blight, plum leaf
scald, and assorted viruses. Large infestations of leafhoppers create clouds
of insects in orchards and are irritating for orchard workers. Leafhoppers are
found across North America.
Programs that control aphids also work well for leafhoppers. It is very im-
portant to implement control programs early, before bloom, to prevent pop-
ulations from building. Eggs are deposited on the host plant in cracks in
the bark. The first larvae begin emerging at about the time of bloom. Ap-
plying dormant-type horticultural oil sprays at the beginning of bud swell
through green tip may help smother eggs. Because these are sucking insects,
ingestion-type pesticides have little effect on them. Azadirachtin products,
insecticidal soap, and Surround appear to offer the best controls during the
growing season.
Mites
Many mite pests infest pome and stone fruits in North America (see box on
defoliation that weaken the trees. Eriophyid mites are very small and cause
similar symptoms to those of spider mites, but some can also cause leaves to
become deformed and develop blisters, galls, and velvety or discolored areas.
Feeding on flower clusters early in the season can also cause fruit deformit-
ies. Otherwise, healthy trees can support large mite populations without ser-
ious harm.
