New York’s experience helps others manage golden nematodes

New York’s nearly 70 years of managing goldennematodes (GN, Globodera rostochiensis) is provinguseful beyond its borders.

Golden nematodes were first identified in North America on Long Island in 1941, likely arriving aboard World War I military equipment returning from Europe. By 2002, 6,000 acres of potato fields in nine counties in New York, plus two Canadian provinces, were known to have GN. In 2006-07, GN was discovered in Quebec and Alberta and the similar pale cyst nematode (Globodera pallida) was found in Idaho.

Golden nematode eggs and juveniles on potato roots.

GN has been a quarantine pest since 1948. GN affects potato, tomato and eggplant crops and some solanaceous weeds, with potato crop loss as high as 80 percent. Outbreaks may resemble water stress, drought and crop mineral deficiency, with patches of poor growth, yellowed and wilted foliage and small tubers. Confirmation of GN requires lab analysis.

Cornell University Plant Pathologist Keith Perry oversees New York state’s Foundation Seed Potato Program. He says, “With the recent outbreaks of GN, we have seen keen interest from other areas of North America. A lot can be learned from New York’s experience with golden nematodes and our three-pronged management program that uses mandated quarantine and field surveying, resistance breeding and our secure seed stock production facility.”

GN-resistant potato varieties await testing in the lab at Uihlein Potato Farm, Lake Placid, N.Y.

USDA ARS Nematologist Dr. Xiaohong Wang says, “The most economical and environmentally friendly solution to control this devastating potato pest is to grow GN-resistant potato varieties.

“Our nematode research program, based at Cornell University, is the only program in North America that conducts both basic and applied research on GN and supports the critical need for developing GN-resistant varieties,” Wang says. “As the only U.S. facility that can perform GN-resistance screening, our program annually evaluates hundreds to thousands of breeding clones developed at Cornell and from potato breeding programs at universities in Maine, Wisconsin, Oregon, Michigan, Colorado, North Dakota and Texas, as well for Frito-Lay, Inc., the Canada Potato Research Centre and the USDA-ARS breeding programs in Idaho and Maryland.”

In 1966, the USDA ARS-Cornell potato breeding team released Peconic as its first of now more than 21 GN Ro1-resistant varieties. As they worked on Ro1, the only known race of GN in the U.S. at the time, team members nudged along efforts to build resistance to other races. In 1994, Ro2 was identified in New York and found to be able to reproduce on Ro1-resistant varieties.

USDA ARS Nematologist Dr. Xiaohong Wang and her Support Specialist David Thurston check GN cysts on the root system of a Cornell University Potato Breeding Program clone in the Wang Lab at Cornell University in 2010.

Cornell Plant Breeder Dr. Walter De Jong says, “The assumption is that Ro2 is present as part of the original GN infestation, but at low levels. When varieties resistant to Ro1 are grown, Ro2 has an opportunity to become dominant. For several years, 90 to 100 percent of the seedlings we plant have segregated for resistance to Ro1 and 20 to 25 percent for race Ro2. We have few good parents that are highly resistant to Ro2 and very few offspring are highly resistant even when one parent is highly resistant. The most likely explanation is that high levels of resistance to Ro2 require multiple resistance genes to be present; since few offspring get all these genes, few are highly resistant.”

De Jong says NY140 is the most promising Ro2-resistant candidate under evaluation: “Its tubers are large, smooth-skinned and have excellent yields, but, like all potatoes, they also have a weakness and are quite susceptible to common scab.”

Perry adds, “It takes 11 to 13 years to develop a viable GN-resistant variety for commercial production. Each variety we add to our germplasm widens the base of resistance and makes us more likely to resist and respond to any new strain.”

New York may begin issuing commercial-use Ro2-resistant varieties in two to three years.

New York’s official certified potato seed stock facility is the Uihlein Potato Farm, operated by Cornell’s College of Agriculture and Life Sciences, 2 miles south of Lake Placid in the Adirondack High Peaks.

Geographically isolated at 2,100 feet above sea level, the farm has an 80-day, cool-climate growing season. Strict protocols restrict human traffic. No tubers or soil-bearing plants are brought onto the farm.

Plants delivered in test tubes from Cornell are tested in the tissue culture laboratory to confirm absence of common potato viruses, bacteria and fungi before being multiplied for planting in a 125-foot greenhouse. Greenhouse-grown tubers move to third-year field production. Approximately 35 acres of potatoes are grown each year for sale to commercial growers producing certified seed for farms that supply end users.

Potatoes and Nematodes

Ron Edgley of Windy Mountain Farm grows 200 to 240 acres of seed stock potatoes 1 mile from the Uihlein Potato Farm.

“If you do not have the nematodes, you should be able to prevent them with good practices. Our main advantage is isolation from other growers and potential contact with GN. We do not buy equipment at auctions in any area known to have GN. We rotate our crops. We use a nematicide and have been trying biofumigants to keep other nematodes in check. Our fields are surveyed each year, and we store our seed separately,” Edgley says.

Ralph Child’s Malone, N.Y., farm is 10 miles south of the Quebec border. He says, “We follow practices to make sure nothing of any kind develops here. Our equipment is steam sanitized. We rotate our fields. I am confident we are OK, and most of the commercial growers know the systems we have in place to stay that way. The annual USDA clean soil report is just reassurance.”

Steuben County, N.Y., grower Gary Mahany says, “New York has done a good job of keeping GN under control. Most people do not realize the huge impact of that. Other states used to think the nematodes were just a New York problem. If not for the success of the nematode program here, you would not see soybeans, ornamentals, trees, potatoes or anything grown in dirt leaving the United States.”

“One hundred years ago there were more acres of potatoes grown in New York than in any state since,” he adds. “New York has the brain trust here, and this would be a great place for a new lab to help control potato cyst nematodes for the entire potato industry in North America.”

New York’s largest privately owned commercial potato seed stock producer, Ralph Child, says, “The Uihlein Farm produces the early generation material that I plant to resell, and is especially important as newer resistant varieties are developed.”

Laboratory Manager Chris Nobles says about 30 percent of Uihlein’s stock is sold to out-of-state buyers.

Empire State Potato Growers Association Director Melanie Wickham says, “New York has been wildly successful in containing golden nematodes and developing resistant varieties. This success is vital not only to growers here, but to growers across the nation and to our international trading partners.”

Wickham says Japanese buyers interested in Washington-grown potatoes first visited New York to assure themselves all GN safeguards were being taken to contain the nematodes.

De Jong says, “Even prior to identifying GN in Quebec, Canadian researchers visited here to learn how we manage GN. We had been sending varieties to Quebec for agronomic evaluation. Many of our varieties grow well there, so the Canadian growers had an immediate supply of GN-resistant varieties from New York to help manage the outbreak there.”

Lisa Gauthier of the Canadian Food Inspection Agency says, “Information and potato varieties generated by Cornell University have been valuable to Canada in expanding options to suppress GN populations. Information on surveys, releasing of land from regulatory control and use of best management practices to control and prevent the spread of GN is shared regularly between the U.S. and Canada. Since the detection of GN in Quebec and PCN in Idaho, there has been renewed interest for the selection and adoption of resistant varieties to help combat any possible infestation.”

In 2006, G. pallida was identified in Idaho in 11 fields, affecting approximately 1,000 acres. Idaho Potato Commission Vice President for Legal and Government Patrick Kole says, “New York’s history with golden nematodes was most assuredly valuable in an instructive way as we considered how to deal with the potato cyst nematode here. By their very nature, potato cyst nematodes are survivors. When the government cut expenditures [for GN control], efforts switched to managing rather than eliminating GN. We learned from New York growers that with the will to see the eradication effort to completion, New York might have eradicated the pest, and would not now need funding for expensive management techniques. Idaho has committed long-term to eradication.”

Michigan’s potato industry has a $160 million farmgate value. Michigan State University Geneticist Dr. David Douches says, “Cornell is the one place in the country breeding for GN-resistance. Using indirect selection of New York’s GN-resistant varieties saves Michigan’s potato breeding program time and money. We screen plants for a DNA marker that indicates a high probability that resistance is there before we commercialize the variety.”

Douches, co-author of “Marker-Assisted Selection for Resistance to Golden Nematode in Potato,” says, “Even though Michigan has not identified GN here, we believe it is worthwhile to begin developing GN-resistant varieties that meet the needs of Michigan growers. By doing so, we ensure that if GN ever becomes a problem in our state, acceptable potato varieties will be available to avoid losses due to this pest.”

Perry notes, “If the nematode would be allowed to spread, it would have an enormous influence on trade, not only in potatoes, but on all commodities with adhering soil.”

The author is a freelance writer who keeps horses and sheep on a 100-acre farm in Mannsville, N.Y.