Heading Off Grape Berry Moth

An adult berry moth (left) will lay its eggs in grapes; larvae within the grapes produce the silk webbing seen on the Concord cluster in the center. On the right, a mature grape berry moth larva emerges from the grape. PHOTOS: Greg Loeb

HIGHLIGHTS

- Some 35 winegrape growers were among attendees at the 27th Annual Long Island Agricultural Forum in January.

- Grape berry moth is an insect pest that can lead to botrytis and other rots, especially if summer temperatures rise too early in the season. Pesticide application is only recommended when economically viable.

- Cornell's Suffolk County extension has put together a workbook to help local growers farm sustainably.

- As in other agricultural areas, Long Island's farm workers are largely undocumented, and new immigration policy is sorely needed.

Approximately 380 farmers, roughly 35 of them winegrape growers, heard the latest advice on controlling grape berry moth in January at the 27th Annual Long Island Agricultural Forum, which took place at Suffolk County Community College in Riverhead, N.Y. Pest control was a timely topic for winegrape growers during the two days of networking and lectures that included grape entomology, pest management, pesticide handling and disposal, and illegal immigration, among others.

Greg Loeb, an associate professor with Cornell's department of entomology, who is based at the New York State Agricultural Extension Service in Geneva, N.Y., kicked off the pest management portion of the program by presenting an overview of the entomology department, the biology of the grape berry moth and the efficacy of various pesticides against it, and concluded with a talk about other insects that may occur in Long Island vineyards in the future.

"There are signs that a lot of chemicals not yet labeled in New York will turn out to be effective against berry moth," said Loeb, who has been studying the effects of insects on grapevines since 1995.

Although historically the species has not had a major presence in Long Island vineyards, Loeb said, a noticeably more widespread infestation that occurred in the region last summer prompted him to dedicate a lecture segment to the life cycle of the insect, which poses a threat by creating wound sites on grapes that can later be susceptible to fungal diseases like botrytis and sour rot, among others.

"The key message is that farmers need to pay attention to heat accumulation in the early part of the season, because if it gets hot early, then there will be an extra generation in August," said Loeb, who pointed out that most growers are thinking about harvest by then.

He encouraged his audience to evaluate their own economic threshold for crop injury when considering the use of sprays. "If the grape berry moth is affecting only half a percent of clusters, then the damage caused may cost just as much as spraying insecticide," he said. "But if 5% of clusters are getting diseases, then it may be worth it to spray for it. We don't know what the threshold level is yet for vinifera grapes."

His department is currently pursuing the purchase of land on which it can raise cold-sensitive vinifera grapes.

Loeb concluded with a discussion of other pests that may or may not inflict damage on Long Island vineyards in the future. The population density of soft scale insects and mealybugs, both vectors for the leafroll virus, Loeb said, does not yet seem to be causing widespread damage on Long Island. He urged caution in the use of broad-spectrum pesticides against Japanese beetles, which are common in the region, because many of them have an adverse effect on the natural predators for spider mites. Two pesticides, Assail and Avant, have proven to be effective against Japanese beetles while leaving spider mite predators intact.

IPM trials

Researcher Steve Hesler from Cornell University sets a sticky panel trap in a Concord vineyard. Red rubber septa contain a synthetic version of volatiles produced by grape foliage that attract female grape berry moths.

Tim Weigle, who serves as the statewide director for integrated pest management (IPM) for Cornell and Penn State's cooperative extension program out of the Cornell Vineyard Laboratory in Fredonia, N.Y., gave an overview of the IPM program, and presented the results of his trials in managing berry moth infestation through both predators and mating disruption.

"You can't go from conventional insecticides to new insecticides (without having an impact on the efficacy of those methods)," Weigl said. Effective pest management, he said, requires "a combination of new and conventional insecticides, and mating control and biological control."

Alice Wise, a senior extension resource educator with Cornell's Suffolk County Cooperative Extension Association, who chaired the viticulture portion of the program, opened the viticulture session with an update on a Chardonnay trial begun in 1993 that is about to be renovated. In addition, Wise discussed the sustainable viticulture workbook that was published late last year that is now open to all growers, rather than merely trial participants. Wise said that the program is still being refined--one of the challenges being how to administer it.

"A third party certification system instills faith (in the program) and encourages participants to be good stewards of the environment," said Wise, who has studied similar programs in states such as California and Oregon, where programs are run by growers.

"You can't take California's (workbook) and slap it down here," she said. "There are economies of scale to consider. We are small here in Long Island; if you've got 15, you've got everybody."

Political issues

Additional highlights of the conference were the appearance by Congressman Tim Bishop, who represents the First District on Long Island; and an update on the New York State Department of Environmental Conservation's Pesticide Program.

Bishop spoke about the farm bill currently on its way to the president (and not immune to a veto), which he said includes significant increases in subsidies for specialty crops, and allocates funding for mandatory pest and disease detection. In addition, he provided an overview of how proposed changes in estate taxes could affect Long Island farmers, and outlined his support of comprehensive immigration reform, which he said should consist of four components including strict border protection; tough internal enforcement; a good guest worker program; and a legitimate path to legalization.

"Seventy percent of agricultural workers in this country are illegal, so we have to fix the problem so that we can feed ourselves and feed the world," Bishop said.

Joe Gergela, executive director of the Long Island Farm Bureau, like other observers of the issue, conceded that a significant portion of the 8,000 agricultural, horticultural, and landscape workers on Long Island are illegal immigrants, although formal statistics are not compiled. "It's a complicated issue that's been in need of fixing for 20 years" Gergela said. "These workers play a vital role in our economy."

Maureen Serafini, who oversees the Bureau of Pesticides Management for New York State's Department of Environmental Conservation, recapped the success of the Clean Sweep Program, reporting that, to date, some 545,000 pounds of chemicals have been collected from 1,143 registrants.

The program, designed to safely and legally dispose of obsolete and unauthorized chemicals, will kick off the week of March 31 and offer amnesty to all participants, likely to include farmers and owners of farms as well as schools, cemeteries and golf courses, among others.

The 27th Annual Long Island Agricultural Forum was sponsored by the Suffolk County branch of the Cornell Cooperative Extension, the Long Island Farm Bureau, and the Long Island Horticultural Research and Extension Center, and others.

Based in New York, Suzanne Gannon writes on travel, culture, food and wine. For the past two years, she has reported on a variety of topics for Wines & Vines. Reach her through edit@winesandvines.com.