| Numerous species of leafhoppers and planthoppers are found in
Missouri, and many of them have a broad host list
(for example, the potato leafhopper, Empoasca
fabae, has over 100 host plants). They feed on
foliage and shoots of many different plant species by
piercing the plant cells and sucking out the contents.
The damage that results from feeding depends on
the host plant and the specific hopper. Only a
few species of hoppers transmit pathogens such
as those that cause curly top virus and aster yellows.
Adult hoppers are excellent short-distance
jumpers when disturbed, and they can be pests
when found in high numbers.
Symptoms and Diagnosis
Hoppers are agile insects that can move with
equal ease either forwards, backwards, or sideways
like a crab. The crab-like motion distinguishes
hoppers from most other insects. In addition,
they can hop to escape danger or to move to
another host plant.
Feeding damage from some species causes small
white spots (stippling) to appear on the upper leaf
surface, usually beginning near the leaf midrib.
Stippled areas can unite into larger whitish blotches
on mature leaves. With some plants, feeding damage
causes a drying and yellowing (or browning) of leaf
margins, and possibly the whole leaf. Some
leafhopper species cause curling or stunting of
terminal leaves with their feeding. Another sign of
feeding is the presence of tiny varnish-like spots of
excrement on the underside of leaves. Also, check
under leaves for white, papery cast skins that remain
from the molting process.
The lacebug is another insect that causes stippling
from feeding and leaves dark droplets of varnish-like
excrement on the underside of leaves.
Distinguishing lacebugs from leafhoppers is easy:
Lacebugs have a lacy pattern on their upper side,
they don't jump or run sideways, and they are about
half as broad as they are long. Yet another pest that
can cause stippling is the spider mite. Check under
leaves for the webbing left by spider mites
(leafhoppers don't leave webbing).
Life Cycle
Adults of most species of leafhopper range between
1/8 to 1/4 inch long. They are slender and frequently
have an angular, pointed head. Coloration depends
on species, but generally leafhoppers are shades of
green, brown, or yellow and are often mottled.
Nymphs (immatures) look similar to the adults except
that the nymphs are smaller and don't have wings.
Nymphs typically feed on the underside of leaves,
where the humidity is higher and they are more
protected from predators.
Leafhoppers have several generations each year.
Some species migrate south in winter and return
north with late spring weather.
Integrated Pest Management Strategies
1. Live with the pests. Because of their mobility and
abundance, leafhoppers are not easy to control.
However, leafhoppers are seldom present in large
enough numbers to seriously injure plants. In
addition, leafhoppers have many natural enemies,
including lady beetles, lacewings, damsel bugs,
and spiders. They are also subject to diseases and
parasites that help keep their numbers down
under most conditions.
2. Use row covers. Floating row covers or netting
can be placed over plants early in summer to
exclude leafhoppers. Remove row covers when
the plants begin to flower.
3. Monitor with sticky traps. Many leafhoppers are
attracted to yellow sticky traps which should be
placed close to the foliage of the crop. Populations
can be monitored with sticky traps and low
populations can be managed using these traps.
4. Apply insecticidal soap. Insecticidal soap can
control leafhoppers if applied when the insects
are small. The immature leafhoppers are usually
found on the underside of leaves so be sure to
spray there also.
5. Apply insecticides. Other insecticides available
for leafhopper control include botanical
pyrethrins, carbaryl (Sevin), malathion, bifenthrin, cyfluthrin,
bendiocarb (Turcam, Closure), disulfoton (Disyston),
and acephate (Orthene). In general, these
are most effective on the immature leafhoppers
because they can't escape as well as the adults
and are typically more susceptible to chemicals. | 
