Eastern Grape Leafhopper: Not a Picky Eater, But Only Has Eggs for Grapes
By Jody Green, Ph.D.
Eastern grape leafhopper (Erythroneura comes) has been documented to be a pest of vineyards for nearly 200 years. It is a key pest of grapes in central and northeastern United States and Canada. “In high densities, feeding by Eastern grape leafhopper may cause a reduction in the number of grape clusters, sweetness of the grape berries and, in severe infestations, stunting of the vine,” says Kevin Jarrell, conservation technician at the George Miksch Sutton Avian Research Center in Oklahoma and a former graduate student in insect ecology at Oklahoma State University. “It’s difficult to quantify the damage it does in terms of dollar value, but it has the potential to negatively impact wine and table grape production.”
Jarrell and fellow researchers from the Department of Entomology and Plant Pathology at Oklahoma State University provide a comprehensive profile of Eastern grape leafhopper in a new report published Monday in the Journal of Integrated Pest Management.
Eastern grape leafhoppers overwinter as adults in leaf litter and debris, sometimes in the crop and other times in the landscape adjacent to the vineyard. Leafhoppers become active in the spring and feed on an extensive range of plants, weeds, and grasses before finding and feeding on the new foliage of grapevines. Although they are able to thrive feeding and mating on many other host plants, they are only known to oviposit (lay eggs) on wild and cultivated grape.
Oviposition and feeding by nymphs and adults result in stippling of leaves, chlorosis (loss of green coloration), early leaf drop, and stunting of affected shoots. Although eastern grape leafhoppers do not feed on the fruit itself, indirect feeding over consecutive seasons may result in permanent damage. Damage is also exacerbated by environmental conditions that result in higher egg laying and therefore population growth. Jarrell says, “The unsightliness of the insects’ excrement on grape berries, and the sooty mold that grows as a result, also lowers the quality of the product.”
Depending on geographical region, eastern grape leafhopper may have one generation per year as it does in New York, or three to four generations as recorded in Oklahoma. The number of generations is dependent on temperature, photoperiods, and rainfall. Challenges in management involve the marketable product, phenology of grape variety, and understanding degree-day models specific to geographic range.
Getting to know the phenology of eastern grape leafhopper began as a senior project for Jarrell, which later evolved into a master’s research project. “The insect and its many congeners are fascinating to me, especially their ecology in the vineyard ecosystem. Observing them in their habitat and reviewing the literature has shown me that, contrary to my previous belief, leafhoppers are anything but boring.”
Jarrell and co-authors outline a number of integrated approaches for the management of eastern grape leafhoppers, which have the potential to provide effective management for multiple insect pests that share ecological niches and geographical ranges. Biological control agents include parasitic wasps, generalist predators, and entomopathic fungi. Together, with cultural, sanitation, and mechanical methods outlined in the article, authors provide options to protect vineyards from eastern grape leafhoppers and continue to provide value in the crop. This is surely good news for growers and good news for researchers working so hard to promote effective and sustainable pest management strategies.
Journal of Integrated Pest Management
Jody Green, Ph.D., is an urban entomology extension educator at the University of Nebraska-Lincoln and a subject editor and communications editor for the Journal of Integrated Pest Management. Twitter: @JodyBugsMeUNL. Email: firstname.lastname@example.org.