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The Grape IPM Team

Teamwork Improves Grape Pest Management Options

Teaming up on the grape berry moth

Grape IPM specialist Tim Weigle is convinced that the most vital aspect of this year’s work on managing an insect pest called the grape berry moth (GBM) was the communication that resulted from it. "This has been the best example of researchers exchanging useful information with growers on a timely basis that I have been involved with," reports Weigle. What were they communicating about? Late-season damage from the GBM. Growers are concerned about it, and researchers are looking for ways to alleviate it.

Fifteen pheromone traps were set out in an effort to determine how many GBM generations there are and when to expect them. Project leaders concluded that more precise information may be gained by trapping female berry moths instead of the males that are attracted by pheromone traps. Future plans are to design traps for the females and to use those trap catch results to improve the timing of insecticide applications. The GBM project was funded in part by the IPM Program and in part by the New York Wine and Grape Foundation.

New methods evaluated for mites, leafhoppers

Tim Martinson, the regional extension specialist for the Finger Lakes Grape Program, tried some new materials for the management of two ubiquitous grape pests: European red mite (a spider mite) and grape leafhopper (an insect). Conventional miticides have been the only option for grape growers who must contend with spider mite infestations.

Martinson found that dormant spray oil, long used by apple growers as the first line of defense against spider mites, has little effect when applied to grapes during the dormant season. "Winter mite eggs on apples are located on exposed twigs," explains Martinson. "On grapes, the same eggs are laid in crevices underneath the bark of two- and three-year-old wood. Dormant sprays on grapes are not effective because it’s difficult for spray residues to come in contact with the protected eggs." However, Stylet oil applied during the growing season did provide temporary relief from spider mites. Three applications before the bloom stage kept the mites away through the end of August. Stylet oil is a plant extract that disrupts insect feeding by clogging the pores of the stylet, an insect’s feeding tube. Stylet oil also controls powdery mildew, giving growers in New York who contend with both pests more for their money.

Grape leafhoppers have developed resistance to the insecticide typically used to manage them, but three new materials have been tried with success. Two of the materials are insecticides. One of these is a new reduced-risk insecticide. It provides adequate protection from leafhoppers with one application and is compatible with biological control organisms. It is more than twice as expensive as the other insecticide, but its environmental and other benefits make it a better value overall. The third material is effective against both leafhoppers and spider mites. Although registered for use on apples, it is not yet registered for commercial grapes. It may become the best option of the three.

Reducing sprays for powdery mildew, black rot

comparison of healthy and diseased grape plants
L: Healthy grape plant; R: grape plant with powdery mildew.
Photos by J. Ogrodnick

Plant pathologist Wayne Wilcox has two years’ data showing that two applications of fungicide should, under normal circumstances, provide adequate protection from the grape diseases powdery mildew and black rot. This is a significant reduction from previous recommendations of four or five applications. "Treatment can be limited to the time period just before and just after bloom," explains Wilcox, "because this is the only period during which the fruit is susceptible to these diseases." In addition to looking at periods of susceptibility, Wilcox achieved success rotating standard fungicides with an alternative treatment, monopotassium phosphate. This foliar fertilizer is another feasible means of reducing the pesticide load on grapes.

A second project on grape powdery mildew is being spearheaded by entomologist Greg English-Loeb. He and his collaborators are looking at fungus-eating mites as possible biological control agents (see "Enlisting Mites to Fight the Number One Grape Disease".)

Managing vineyard weeds: less is more

Reductions in active ingredient of 400 to 670 percent, dollar savings, and excellent weed control are the results of the second year of two postemergence weed management demonstrations. Tim Weigle led a demonstration in the Lake Erie Region, and Tim Martinson led one in the Finger Lakes Region.

Conventional in-the-row weed management for vineyards has involved herbicide applications both before and after weed emergence. The postemergence strategy has the potential to cut the number of applications in half by limiting them to the time after weed emergence. The ten growers who allowed portions of their vineyards to be used for these demonstrations saw firsthand that postemergence weed control was equivalent to the control achieved in the plots that were given conventional treatment.

Electronic crop updates improve communication

A new method of information transfer was introduced last year by the grape IPM team, thanks to the leadership of Extension Educator Tim Martinson and IPM Extension Educator Tim Weigle. They modernized and expanded on weather and pest information that has been disseminated by a telephone message ("Code-A-Phone") and sent the information out via e-mail. Seventy-five growers, Extension field staff, administrators, researchers, and food processor representatives signed up to receive these electronic "crop updates," and the list of recipients continues to grow. Weigle finds the e-mail delivery system "…an excellent way not only to get information out to the industry but also to collect input from the industry as to crop- and pest-related events during the growing season." The new crop update system has also prompted growers and others to use e-mail to ask questions of the grape team. Martinson says he has received more positive feedback from the grape industry on this than on any other project.

Introducing the grape team

Rick Dunst, research support specialist and manager of the Taschenburg Lab in Fredonia, did the research for the postemergence weed management projects.

Greg Loeb is an entomology professor at the Experiment Station in Geneva (NYSAES). He collaborated on the projects concerning grape berry moth, European red mite, and grape leafhopper management. He also led a project on managing powdery mildew with beneficial mites (see "Enlisting Mites to Fight the Number One Grape Disease" elsewhere in this report).

Growers who devoted part of their acreage to the postemergence weed management projects are Ed Barger, Jr., Joel Rammelt, and Bill Dunn.

Sudah Katti and Mike Saunders, entomologists at Penn State, studied the biology of the grape berry moth and shared their findings with those working on this pest at Cornell.

Tim Martinson is an Extension educator with the Finger Lakes Grape Program. He led a three-faceted project on the European red mite, the grape leafhopper, and postemergence weed management (Finger Lakes Region).

Andy Muza, Extension agent from Erie County, Pennsylvania, worked on the grape berry moth project and the electronic crop updates.

Robert Pool, horticultural sciences professor, NYSAES, assisted in the development of the postemergence weed management protocol.

Barry Shaffer, Cooperative Extension educator at the Lake Erie Region Grape Program, specializes in farm business management. He worked on the economics of grape berry moth management and helped with the electronic crop updates.

Phil Throop, team leader at the Lake Erie Region Grape Program, helped prepare the electronic crop updates.

Tim Weigle is an IPM Extension educator based at the Lake Erie Region Grape Program headquarters. He covers grapes statewide, focusing mostly on the Lake Erie and Finger Lakes Regions. Tim headed up the projects on grape berry moth and on postemergence weed management (Lake Erie Region).

Wayne Wilcox, plant pathology professor, NYSAES, conducted the study on powdery mildew and black rot. He also collaborated on Tim Martinson’s project.