The Tribune Democrat, Johnstown, PA

June 19, 2010

Experts: Tomato blight is back

By Kathy Mellott
kmellott@tribdem.com

JOHNSTOWN — The fungal pathogen that last year forced many gardeners to endure styrofoam-like tomatoes at inflated prices is back and unless the weather turns hot and dry, the result could be even more devastating, experts said.

The tomato/potato late blight, which devastated home garden crops so quickly it prompted one local woman to compare it to a blowtorch, has been found in the region one week earlier than the first blight detected in 2009, a Penn State vegetable expert said.

Tom Ford of Penn State’s Cooperative Extension office covering Cambria and Somerset counties said the outlook for healthy home garden tomato growth this season could be bleak.

“I am actually very worried at this point,” he said. “If it gets warm and dry we may be OK, but these little cold fronts are especially bad for Cambria and Somerset because of the mountain areas.”

During the week of June 10, Ford responded to a call at a community garden at a monastery in Blair County. What he found was alarming.

Late tomato blight was confirmed on what Ford estimated to be 50 to 75 tomato plants.

Raised in Indiana or Jefferson County, the plants were traced to a retail greenhouse in Somerset County, creating concern that many gardeners in Cambria County may have some of the infected plants, he said.

“It’s just a matter of time before we see more,” Ford said.

Officials are not identifying the Somerset business that sold the infected plants.

Beth Gugino, a Penn State vegetable extension pathologist, said the local discovery is disconcerting.

“We’re concerned in Somerset because we think a lot of infected plants may be transplanted in home gardens,” she said.

Glen Rosage, owner of Westwood Garden Haven on Goucher Street, said he and his staff are working as they always do to prevent any problems from getting into home gardens.

“We keep them clean here. If it happens it will be when they get them out (in the garden),” said Rosage, a 40-year garden center veteran.

Bob Pollock, Penn State Cooperative Extension director in Indiana County, also has seen plants that show signs of tomato blight and have been submitted to a lab for analysis.

“We need to keep our ears up and our eyes open,” Pollock said.

In 2009, the same fungal pathogen known as phytophthora infestans was recorded from New York to Wisconsin, wiping out many home garden tomato crops. It is the same blight that caused Ireland’s potato famine 150 years ago.

It is spread through spores carried by rain, wind, people, machinery and wildlife.

Wind can blow late blight spores up to 30 or 40 miles, Gugino wrote in a cooperative extension publication “Tomato/Potato Blight in the Home Garden.” Spore survival is greatly reduced when relative humidity is below 95 percent.

The spore spread through wind could be problematic for Pennsylvania, Ford said.

“It started in Florida and worked its way up the East Coast,” he said. “It hit the Midwest late last year, and we all know know the wind travels west to east.”

Historically, late blight has been an ongoing issue in commercial potato production, where growers know what to do and take aggressive action, Gugino said. But the cool, wet weather of summer 2009 coupled with infected transplants sold at garden centers caught home gardeners unaware.

“People didn’t really know what was going on. We’re hoping people are more aware of it,” she said.

Garden centers across the region report that public awareness of tomato blight is high.

“Some people are taking measures to prevent it,” said Rosage. “I hope we don’t have two bad years in a row.”

 

PLANT PROBLEMS

What to look for:

• Pale green to brown spots on upper surface of leaves.

• Lesions on leaves.

• Downy white growth may develop.

• Stems, branches and eventually fruit may be infected.

• If suspected, contact county Penn State Cooperative Extension office. Cambria County residents should call 472-7986; Somerset residents, 445-8979

What to do:

• Before symptoms appear, spray with fungicide containing chlorothalonil.

• Most common trade names are: Daconil, Bonide, Fung-onil and Ortho Multi-Purpose Fungicide.

• Reapply every five to seven days through growing season.

• Reapply after significant rain.

• Destroy infested plants.

•Follow label directions, including protective clothing if recommended.