August 7, 1995 in Nation/World

Late Blight Threatens Potato Crop Western Idaho Fields Devastated; Farmers Use Fungicide To Fight Blight That Caused Irish Famine

By The Spokesman-Review
 

The state famous for potatoes is having an outbreak of the blight that caused the great Irish potato famine.

“It’s real scary,” said Bill Hartman, a fourth-generation farmer who’s seen 25 percent of his potato crop stricken by the blight.

So far, the infamous late blight has shown up in nearly all of the 8,000 acres of potato fields in southwestern Idaho. That’s the area that usually starts up the french-fry factories and other processors each year with its early harvest potatoes.

But farmers’ and state agriculture officials’ worst fears are that the blight could spread to the prime potato-growing regions to the east, which nurture most of Idaho’s famous baking spuds.

So far, it hasn’t.

Just to make sure, farmers across the state are dousing their fields with fungicide to kill the blight. The Environmental Protection Agency has granted emergency approval for four new chemicals to combat the blight, which is resistant to regular fungicides.

In Parma, the spray planes are up just about every day. They roll on their sides in the air, line up, then swoop low over fields, shooting plumes of spray into the hot, still air.

The new fungicides were cleared for use in Idaho within five days, said Mel Anderson, executive director of the Idaho Potato Commission. “That’s a record for us.”

There’s plenty of reason to act quickly. The late blight is so aggressive that, if left undetected, it quickly can kill the whole potato plant. It starts as a dark spot on the leaf and progresses to a gray mold on the leaf’s underside. Once it reaches that stage, it can spread quickly in the wind.

Not only is this the same stuff that decimated Ireland’s potato crop in the 1840s and prompted thousands of Irish to immigrate to the United States, but it also is a newer, more aggressive strain.

Jessica Vickers, a potato scout for the University of Idaho’s agricultural extension service in Parma, recalled a local farmer who went on vacation just after blight had been spotted in his potato field. When he returned about five days later, there was a “big dead spot” in his field.

“Some of them weren’t too concerned about it until they lost their crops,” said Vickers. “The ones who have been spraying are doing pretty well.”

About half of the 8,000 acres of potatoes in southwestern Idaho are “severely affected,” said Mike Thornton, extension potato and onion specialist in Parma. “The other half also have late blight, but they’re just being able to hold it back with application of protectant fungicides.”

The southwestern fields are only a small chunk of Idaho’s potato crop. There are 408,000 acres of potatoes statewide.

Other states in the region have had the late blight before, state officials say, but not Idaho. There was one report in a small, isolated field in south-central Idaho in the mid-1980s, but it didn’t spread.

While Washington and Oregon had the problem, many Idahoans thought their state was immune because the fungus thrives in moist, cool conditions. Idaho, especially out in the potato fields in the summer, tends to be hot and dry.

But this year saw a cool, wet spring. And the blight, which may have been imported in seed potatoes, took hold in well-irrigated fields and under the cool canopy created over the potatoes by their leafy vines.

Farmers like Hartman who had been spraying fungicide already weren’t hit too hard by the blight. Right now, he’s spraying every five days.

Hartman, 36, pulled up a shriveled plant in his field and showed where the blight had hit. The muddy potatoes below were smaller than those he unearthed a few feet over. “They’re not going to grow any more,” he said.

But the field was nearly ready for harvest, so the losses there will be minimal.

Driving to another of his fields, Hartman’s pickup rocked along a soft dirt road between rows of crops and a wide, flowing irrigation canal. As the truck approached, a pair of ducks lifted off the canal, then another pair, then another.

Hartman and his brother John farm 1,000 acres, including 160 acres of potatoes. The rest are wheat, barley, seed onions, carrot seed, alfalfa seed, bean seed.

Arriving at a field of russet burbank potatoes, the big bakers, Hartman was pleased to see strong, healthy green vines and no brown spots anywhere. That field has held off the blight.

“I’m not in a huge big panic about it, other than I don’t want it around,” Hartman said. “I hate to see the disease in the area.”

, DataTimes ILLUSTRATION: 2 Photos

MEMO: This sidebar appeared with the story: POTATO BLIGHT The late blight that has stricken southwestern Idaho is so aggressive that, if left undetected, it quickly can kill the whole potato plant. It starts as a dark spot on the leaf and progresses to a gray mold on the leaf’s underside. Then it can spread quickly in the wind.

This sidebar appeared with the story: POTATO BLIGHT The late blight that has stricken southwestern Idaho is so aggressive that, if left undetected, it quickly can kill the whole potato plant. It starts as a dark spot on the leaf and progresses to a gray mold on the leaf’s underside. Then it can spread quickly in the wind.


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