MADRAS – In this large field where green, healthy garlic leaves stretch toward the horizon, the tiny patch of yellow that plant pathologist Fred Crowe stood over one recent June day seemed innocent enough.

The swath of dead leaves counted maybe 30 plants among its victims. Close by, smaller patches stood, radiating out like the arms of an octopus. Beneath the dry leaves, hidden by soil, garlic bulbs rotted.

”There’s one here, there, one over there, and over there, and you’ll probably find a dozen more just as easily,” Crowe said, pointing out the hapless plants.

Nearly 700 plants in all were likely felled in a strike of white rot that shocked its farmer, Crowe said. Although not a large infestation, the bulbs would have to be sold for dehydration rather than seed – virtually eliminating profit.

It was deep beneath the field of knee-high plants, however, where the true measure of damage lay. There, among a long and tangled root system, crept a white, fluffy fungus that has hibernated in Central Oregon soil for decades.

Spread by tiny masses of thread that look like poppy seeds, the innocent-looking sclerotia, as they’re called, may spell the end for the local garlic industry.

Crowe, a man who’s dedicated his life to thwarting a fungus some call the AIDS of garlic and onion crops, pulled up some roots covered with the notorious pathogen.

”This is not a first stage situation. If it had been missed this year, the farmer probably would have lost a quarter of his field the next year it was planted,” Crowe said. ”This cycle keeps occurring over and over again, all over the world, and people never respond to it quickly enough, never anticipate it.”

It’s planted on only about 2,100 acres of local land, but garlic seed is one of Central Oregon’s most profitable crops. Sold for about $.14 per pound, the specialty crop, which supplies seed for the California garlic industry, netted almost $4 million in 2003.

For more than 20 years, seed companies in the San Jouquin Valley have relied on local farmers, whose skill with niche crops combined with the region’s weather and high altitude and latitude, produces a clove that flourishes in California soil. But the same seed companies that have pumped millions into the local economy also, unknowingly decades ago, started tracking pinhead-sized sclerotia in with them.

HERE WITH A VENGANCE

Already blanketing more than 10,000 acres in and around Fresno, and responsible for the collapse of the garlic seed industry in the Tulelake Valley, white rot has dabbled only lightly in Central Oregon in past years. Now, however, after years of underground growth, it’s here with a vengeance, plant experts and farmers say.

”It’s to the point where it’s almost unacceptable to farmers and seed companies,” Crowe said.

The disease has already taken the Agency Plains above Madras out of garlic production, pushing growers into Culver and Prineville. A survey of fields early this summer found 21 new strikes of the fungus – far greater than any one year’s ever seen, said state inspector Martin Zimmerman. At least 15 percent to 20 percent of garlic fields have been hit with the pathogen, Crowe estimates. One strike south of Madras took out an entire field, destroying thousands of bulbs.

But most often, it’s not rotten bulbs that account for most damage – it’s no bulbs at all. Seed companies fearful of spreading more of the pathogen through California fields are already abandoning local soil.

”You just have to have zero tolerance. You can’t tolerate any contamination (in seed) with this particular fungus because it lasts so long,” said Don Ross, seed production manager for Sensient Dehydrated Flavors of Turlock, which has already decreased contracts with local farmers by 60 percent. ”Next year will probably be our last year.”

The region’s largest seed contractor, ConAgra Foods of Hanford, Calif., has yet to sign contracts with its usual roster of farmers for planting next season.

”It’s a situation where we could have virtually no garlic in this area next year because of the problem,” said Culver farmer Mark Hagman, whose 55 acres of garlic were hit hard with white rot this year. ”It’s becoming increasingly difficult to find virgin ground.”

AGGRESSIVE FUNGUS

A famously aggressive fungus that spreads rapidly and – in its early years, silently – through root systems, white rot has confounded western plant pathologists since it first hit California in 1939. Once established in a field, it is impossible to eradicate. Its fruiting bodies, sclerotia, are spread to new fields by clinging undetected to harvesting equipment, bins, trucks, cloves and more. Over short distances, it can be spread by animals and running water.

It lives only in the presence of garlic or other members of the allium family, which includes onions and leaks, among others. White rot is most deadly to garlic, however, because garlic doesn’t form a true seed and sclerotia cling readily to the cloves that are planted instead. Grown over the winter, garlic is also more susceptible because the fungus sleeps in warm weather and wakes up when its cold.

The sclerotia, which can survive in soil for at least 30 years, are activated by the gases and vapors that allium roots leak. This activation method goes to the heart of the fungus’ power. While most fungi must come in direct contact with a plant root to wake up, garlic’s sclerotia will awaken from as far as an inch away from a root. As few as one sclerotium per 10 kilograms of soil can set off the disease, and one per quart of soil is enough to kill half the plants in a field, Crowe said.

”For most pathogens, it takes a thousand to a million times that,” he said.

Once activated, the fungus can jump to neighboring roots and zigzag underground through an entire row of plants with ease, Crowe said. From there, the fungus climbs up the roots, destroying them as it goes, until it reaches the garlic bulb. Within days to weeks, the bulb rots and dies.

HARD TO CATCH EARLY

The initially slow progression of the disease can fool farmers into complacency. A field’s first strike often slips by unnoticed – first-stage casualties usually claim only a few plants, making the disease hard to spot. But the next time that same field is planted with garlic – farmers normally wait four or five years – the fungus strikes hard, thanks to high populations of sclerotia produced the first time around.

”By the end of the fourth time you harvest that field for garlic, it will kill everything,” Crowe said. ”That’s why people run away from it.”

The pathogen first appeared in Central Oregon in the 1980’s, when four fields were hit, Crowe said. But it wasn’t until the winter of 1990-91, when a freeze destroyed local garlic seed, that the problem really began, he said. To regenerate the seed pipeline the following fall, farmers had to plant cloves from commercial garlic in the Central Valley instead of using cloves produced by their own seed, as was usually done. The commercial bulbs were unknowingly infected with white rot. By 1996, the disease had visited close to 40 fields, Crowe said.

In 1995, local growers and their seed companies established a program that required any imported seed be certified as white rot-free by state inspectors before planting. By then, however, it was too late. The program will likely be abandoned this year because infestation is so widespread, Zimmerman said.

”Unfortunately, in Oregon, the growers and (state) Department of Agriculture were never as aggressive toward this pest as they should have been. In all honesty, the (California) garlic industry wasn’t as aggressive as it needed to be either,” Ross said. ”We certainly are not innocent in its movement.”

Presently, the California garlic industry will not take bulbs from fields infested with white rot. For the Central Oregon garlic industry, that policy can only lead to collapse.

Luckily for local farmers, Crowe, with the aid of some high-powered research, aims to prevent that.

FUNGI CELEBRITY

The nation’s foremost expert on white rot, Crowe is one of a small handful of plant pathologists to have stuck with the disease, which, over the years, has been deserted by researchers weary of failure. In fungi circles, in short, Crowe’s a celebrity. First tackling white rot as a graduate student at University of California at Davis in the 1970s, the scientist, who works out of the Central Oregon Agricultural Research Station in Madras, has for the past decade led a team of pathologists from Mexico to New Zealand in a quest to vanquish the disease.

”He’s generally acknowledged by scientists who have worked on white rot to be an international authority. When I was a young student first beginning to work on (the disease), Fred Crowe was a very big name,” said Dean Metcalf, an Australian plant pathologist who also studies white rot, said.

”A far greater understanding of the way the disease infects crops has been obtained from the work that he’s done.”

Crowe’s research has not been in vain. Experiments he led in fields throughout Mexico, Canada and the western United States – as well as in Madras – in the early 1990s pioneered a substance that many think holds the key to controlling white rot.

POSSIBLE CURE

Called diallyl disulfide, or DADS for short, the pungent substance, which smells like super-concentrated garlic, occurs naturally in the plant but can also be produced synthetically. Applied to infested soil in the absence of garlic, when a field is planted with a rotation crop such as wheat or potatoes, DADS tricks sclerotia into germinating. With no garlic roots or bulbs to feed on, the fungus dies.

Washing soil through mesh sieves to clear it of plant debris, Crowe and a research team painstakingly counted the number of sclerotia before and after DADS in their trial. The results: the odor compound reduced the number of microbes by as much as 99 percent. The chemical works best on fields that are still in the early stages of white rot, Crowe said.

Garlic powder showed similar results in the trials. However, the wide range in concentrations of available garlic powder currently makes it hard to apply, Crowe said. The fumigant methyl bromide also successfully controls the disease, but, costing about $400 an acre to apply, the chemical’s price is not worth the benefit, he said. The fumigant’s toxicity has also come under scrutiny in recent years.

Crowe thinks that DADS, working in concert with a strong fungicide could keep white rot under control in both Central Oregon and California. Add to that better inspection of fields to catch the disease early, and roguing – pulling out and destroying infected plants and nearby soil, a treatment that has met with success in Mexico – and Crowe thinks the region may have a recipe for how to live with the disease.

”None of these approaches by itself is going to totally eradicate white rot,” he said.

TWO HURDLES

But two big hurdles stand in the way. Researchers have yet to find a company willing to manufacture diallyl disulfide – since it helps only allium crops, a relatively small agricultural market, the chemical would net a company little profit. It’s also pricey – as much as $500 per acre if applied twice in a season.

The other hurdle comes from the federal government. The only fungicide that has proven strong enough to last through garlic’s 10-month growing season – tebuconazole, also known as Folicur – is not approved for use on garlic crops. While already available for other plants, the fungicide is part of a group of compounds currently under investigation by the Environmental Protection Agency. New uses are on hold until the investigation is complete.

”We’re really on the edge of being able to live with white rot, but we’re not quite there yet,” Crowe said. ”That’s what’s frustrating, because we’re running out of clean land.”

POLICY OVER SCIENCE?

Despite all the progress that’s been made in stopping the pathogen, the biggest key to saving the local garlic industry may come down to policy rather than science. According to Crowe, the California garlic industry needs to change how it does business.

”The seed companies are going to have to learn to live with a little bit of white rot,” he said.

While companies such as Ross’ Sensient won’t entertain such a notion, Ross admits it’s a hard line to toe. Leaving Oregon forces companies to look for garlic seed in places like Nevada, Colorado and Utah. Moving operations further away significantly hikes shipping costs and eats into profit, he said. In a market facing increasing competition from cheap garlic from China, the California industry may not be able to afford that.

”It costs $1,500 – $1,600 to haul a load from Oregon,” he said. ”I’ve looked into Colorado, and it’s going to cost me about $3,500 from there.”

Farmers say it’s impossible to predict what the next growing season will bring, but some are already scouting around for alternative crops. The cost of hauling garlic seed from other states makes it likely the California industry will maintain at least some presence in Central Oregon in the near future, Hagman, the Culver farmer said. The question is how much, and for how long.

”It’s up in the air right now,” he said. ”Garlic has been a good crop for us for some twenty-odd years. But we know the end is in sight, primarily because of white rot.”

Jeanene Harlick can be reached at 541-408-2606 or at jharlick@bendbulletin.com.