Leaf Damage Caused by the Grape Leafhopper

The leafhoppers that feed on Grapes are reported as:
Empoasca fabae (Harris) - Potato Leafhopper - (by Flaherty, et.al. - minor pest)
Erythroneura elegantula Osborn - Grape Leafhopper - (by Flaherty, et.al. & Flint)
Erythroneura variabilis Beaver - Variegated Grape Leafhopper - (by Flaherty, et.al.)
Erythroneura comes - (by Cranshaw)
Ditrella cockerllii (Gillette) - (by Flaherty, et.al.)

The feeding damage as seen in the accompanying photograph destroys the green photosynthetic ability of the leaves. In Colorado, Hamman (page 56) indicates that this pest seldom reaches sufficient levels to damage the vines. (Note that the photograph was taken in Colorado). Flaherty, et.al. (page 97) consider the grape leafhopper a major pest in California reporting that the insect is capable of defoliating vines by midsummer. Plant damage varies with location, variety and vigor of the vines, with these leafhoppers preferring to feed on vigorous vines.

Excrement and honeydew excreted by leafhoppers drops on and stains the grape berries reducing their quality. Honeydew is a sticky sweet substance that is colonized by sooty mold making the fruit unsightly and unmarketable. Berries on leafhopper damaged plants also have a lower sugar and increased acid content thereby affecting the quality of the wine produced from these grapes.

The Grape Leafhopper feeds on many plants including Virginia creeper, maple, strawberry, burdock and mint (Cranshaw). Controlling leafhopper populations on these and other plants, to include weeds near the vineyard will help reduce leafhopper damage on grapes.

Discing under weeds and soil debris near the vines before spring eliminates the leafhopper's overwintering protection.

Further information and control options are covered in the references. The Cooperative Extension office in your state should also be able to provide you information on grape production and insect/disease control options.

References Used:
Cranshaw, W. 1992. Pests of the West: Prevention and Control for Today's Garden and Small Farm. Fulcrum Publishing, Golden Colorado.
Flaherty, D.L., F.L. Jensen, A.N. Kasimatis, H. Kido and W.J. Moller (eds.). 1982. Grape Pest Management. Publication #4105, University of California, Berkeley.
Flint, M.L. 1990. Pests of the Garden and Small Farm: A Grower's Guide to Using less Pesticide. Publication #3332, University of California, Oakland.
Hamman, R.A.,Jr., S.D. Savage & H.J. Larsen. 1996. The Colorado Grape Growers' Guide: 1996 Edition. Publication 550A, Colorado State University, Fort Collins.
Webb, S.E. 1996. Insect Control in Grapes. University of Florida, Cooperative Extension Service.

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