A child of the Great Plains can pack summer in his cheek, spit the pits and grin with purple teeth.

It's boy against robin, true, but chokecherries filched from the neighbor's yard, or from trees down by the river, are the mouth-puckering fruit of August.

They are prized by alley pirates, stirred by domestic divas into jelly and syrup and fermented by amateur and sophisticated wine makers.

The chokecherry, so humble and so symbolic of the prairie, is in trouble.

Trouble doesn't come from black knot syndrome, which is unsightly but never mortal to the tree, or even from the feeding frenzy of leaf-chomping web worms.

Trouble comes from a more dire direction.

It's called X disease, and based on 100 years of observation, plant scientists believe it wiped out the entire native chokecherry population in the Great Plains in the 1950s and the 1960s.

Whether it did is not entirely certain. Nor is it certain whether that widespread mortality was one prolonged event, or two separate ones.

It is rare to find an old chokecherry tree, says North Dakota State University plant pathologist Jim Walla. He said he knows of only a few that would predate that breakout.

What is certain is that X disease is back, if it ever left. It is threatening chokecherries throughout North Dakota, up and down the Great Plains and into Canada.

It is a pathogenic bacterial disease in the cellular phytoplasmas of the plant. It's carried by leaf hoppers from tree to tree. It shrivels the leaves, stunts the fruit and discolors the foliage, turning it lime yellow in summer and orange in autumn.

It is nearly always fatal while the tree is still a teenager.

This is not good news for a state that only months ago, at the request of Williston schoolchildren, formally declared the chokecherry the North Dakota state fruit.

Stan Lyson, the Williston senator who introduced the chokecherry bill, said it's just too darned bad. Had he known, Lyson said he would have had the schoolchildren research X disease, along with the other learning they pursued in promoting the chokecherry.

Jeff Peterson, co-owner of Pointe of View Winery near Minot, said he'd hate to lose the chokecherries people pick and sell to the winery every summer. Customers like to buy chokecherry wine mainly because it's part of their rural history.

He knows that some years are better than others for chokecherries, but said he wouldn't know if the variance is due to weather, or disease.

Peterson does know it isn't always possible to buy the 500 pounds they like to get to make a couple hundred bottles of chokecherry wine every year.

Lyson said he's glad researchers like Walla and others at NDSU are on the case.

"I have a lot of faith in those people down there at the college," Lyson said. "They'll come up with something."

Society has come to believe that science will always fix what's broken in the world, one way or another.

Walla said he's confident that will be the case with X disease. He said people should understand, first off, that while the disease is the most serious of any problem that affects the fruit tree, it is very unlikely to eliminate it altogether.

That said, Walla and others at NDSU have been on the problem for 14 years. He expects a fix is another five years off.

It won't come by a cure - not like society yearns for with cancer, or diabetes.

It'll come by identifying trees that are resistant to the disease.

It hasn't been easy.

Walla said researchers started by looking at 3,000 chokecherry trees and found a mere 20 among those that appear to be resistant or have a strain that is not very strong. A similar project in South Dakota added 15 apparently resistant trees to the total.

Through the tedious work of grafting diseased twigs onto apparently resistant trees, cloning and tissue culture, researchers are working their way toward developing a resistant seed stock for the future.

The test stock is being grown at the Lincoln Oakes Nursery at Bismarck, where resistance and preferred traits - height, fruit production - can be observed. The cloned trees, all in groups of three, are eerie, like seeing identical triplets everywhere.

Walla planted another 75 chokecherries, all started in tissue culture, at Lincoln Oakes on Wednesday morning.

He said the outdoor setting makes the trees vulnerable to weather, chemicals and other problems, and it's been hard to isolate X disease as the fatal factor. A new grafting, or inoculation study, will be moved into NDSU greenhouses.

"I didn't think it would take that long," Walla said.

On the other hand, he's very confident that somewhere around five years from now there will be resistant stock. How long that stock takes to get to the public for windbreaks, orchards or just a backyard tree is unknown.

NDSU will also study the genetics of X-disease resistant trees.

The same disease is harming not just chokecherries, but all stone-fruit crops, including cherries, peaches, prunes and others grown in commercial orchards.

In this regard, NDSU's work could have national and international applications.

But for now, the focus is on the chokecherry tree, a favorite of alley pirates and the family uncle who brews a batch of homemade wine down in the basement every year.

Some things - surely the chokecherry is one - are worth saving at any cost.

(Reach reporter Lauren Donovan at 888-303-5511, or lauren@westriv.com.)