Aster Leafhopper
Macrosteles fascifrons (Stal), Cicadellidae, HEMIPTERA


DESCRIPTION

Adult - Usually 3.5 to 4 mm long, this light, smokey green to yellowish-green leafhopper may be as short as 2 mm or as long as 5 mm. Sometimes called the six-spotted leafhopper, this species has six black spots arranged in pairs on the front of the head.

Egg - No description.

Nymph - The nymph ranges from 0.6 to 3 mm long. It has the same head markings as the adult but varies in color from yellow or light brown to a pale greenish-gray.


BIOLOGY

Distribution - During the growing season aster leafhoppers can be found from Mexico to Alaska. Habitats as varied as grasslands, swamps, and dry prairies can all support populations of these leafhoppers. Unless they are migrating northward in spring, the leafhoppers usually do not move more than 100 m (about 200 ft) over a 4-week period.

Host Plants - Aster leafhoppers attack a wide range of vegetables, fruits, herbs, grasses, and weeds. Some common vegetable and herb hosts include lettuce, celery, carrot, parsnip, parlsey, dill, onion, shallot, pepper, tomato, cucumber, and sweet corn.

Damage - Nymphs extract plant sap from the underside of leaves and cause a general yellowing of plant foliage. Adults of this species, however, also damage plants by transmitting diseases like aster yellows to carrot, lettuce, and aster. Aster leafhoppers are the only known vector of this disease in the eastern U.S. Infected plants yellow, become stunted, branch excessively, and develop short internodes. Young plants are most affected by this disease.

Life History - The biology of this leafhopper has been studied primarily in northern states or in the laboratory but not in North Carolina. Here, it is believed to overwinter on perennial weeds or fall-planted small grains, probably both as eggs and adults. In spring, adults migrate to other herbaceous host plants. They pick up the aster yellows virus by feeding on infected plants but cannot transmit it until after an incubation period of 10 to 18 days. Viruses are usually transmitted by adult leafhoppers because nymphs molt fairly often and mature into adults in about 18 days (under lab conditions). Thus, the virus often does not have enough time to incubate in nymphs. Adults, excluding overwintering forms, have been reported to live an average of 42 days (on host plants in laboratory). Life cycles as short as 20 days occur in summer in Michigan. Many generations per year are possible in North Carolina.


CONTROL

Fortunately, the leafhoppers and the yellows disease they transmit are rarely much of a problem in North Carolina. Should large populations develop, consult the North Carolina Agricultural Extension Service for current control measures.

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