Courtesy of Mike Klein, Oregon Hazelnut Marketing Board
With hazelnut prices at a record high, farmers are trying to squeeze out as much profit from dying orchards as they can, experts say.
Older hazelnut trees across Oregon’s Willamette Valley are gradually succumbing to Eastern Filbert Blight, a fungal pathogen, while growers replace them with new disease-resistant varieties.
However, at a time when farmers are selling hazelnuts for $1.70 per pound — the highest price ever — they are reluctant to remove infected orchard blocks that still generate solid yields.
“We know it’s a matter of time before we lose the orchard but we’re going to keep fighting,” said Dwayne Bush, a farmer near Eugene, Ore., during the annual conference of the Nut Growers Society on Jan. 13.
Bush said he scouts for symptoms of blight and prunes away infected limbs throughout the winter, then sprays fungicides four times per year after bud break to suppress the disease.
Eastern filbert blight can be slowed by cutting away “cankers” that allow the fungus to release spores and infect new trees, said Jay Pscheidt, plant pathology professor at Oregon State University.
Cutting a branch directly below the canker, however, is not sufficient — more wood must be removed to effectively prevent the canker from growing, he said.
Pruning the limb three feet below the canker will offer the most protection but will also significantly dent production, so Pscheidt recommends cutting one foot below the canker.
Cankers can still release spores after a branch is cut, so growers should not allow pruned limbs to linger on the ground below trees, he said.
If piles cannot be burned immediately, they should be moved to an area where prevailing winds won’t send spores toward uninfected portions of the orchard, Pscheidt said.
Grinding the limbs has also been shown to nullify the threat from cankers, he said.
Fungicides help trees fight the fungus and stave off the decline in yields, but the cost of spraying must be weighed against the revenue from the orchard block, Pscheidt said.
“These fungicides are not 100 percent effective,” he said. “You will still find cankers on the trees, but significantly fewer of them.”
Growers with large trees must also contend with the issue of spray coverage.
Garry Rodakowski, a farmer near Vida, Ore., has trees that are 40-80 years old and have grown too big for cankers to be readily spotted.
Apart from pruning problems, the size of the trees impedes the penetration of fungicides, Rodakowski said.
“Your spray coverage has to get up there,” he said.
Rodakowski’s solution has been to remove the overstory between rows with a hedging machine, creating an opening for the fungicide mist to rise and filter into the trees.
“We’re knocking down about 20 feet from where the original canopy was,” he said.
Bruce Chapin, a farmer near Salem, Ore., hires aerial applicators to treat his trees, which allows him to exploit the few “weather windows” of ideal spraying weather in early spring.
“Timing is very important,” he said.
At this point, one of the orchards managed by Chapin’s family is so diseased that the blight has spread to the trees’ trunks, convincing them to stop pruning.
Even so, they hope to keep the block producing nuts for another 3-5 years with the spray regimen, he said. “Keep in mind, this orchard is still producing money.”