Concorde's fatal flaw
Fireblight has wiped out several blocks of Concorde pears in Washington State.
Background: Dropped Concorde pears. Inset, back: Rudy Prey finds discoloring, showing that the trunk is infected with fireblight. Inset: Most of the trees and crop are gone in this tenth-leaf Concorde pear block.
At one time, the Concorde pear appeared to have a lot of promise in Washington State. It's a crisp, flavorful variety that can be eaten without ripening. The tree's growth habit makes it suitable for high-density plantings, and returns to growers have been good.
But it has one fatal flaw—its extreme sensitivity to fireblight.
Many of the Concorde trees at Rudy Prey's orchard at Peshastin in Washington's Wenatchee Valley, are nothing more than stumps, as a result of a severe fireblight infection this spring. A six-acre Concorde block in about its tenth leaf and just in its prime was devastated by the disease.
Prey, who has 70 acres of pears, said he's had fireblight in his orchard before and lost some trees, but this year's infection took him by surprise. "I didn't even think we had the conditions for fireblight this year. I didn't think it was warm enough. We had a very cool spring, and as far as I can remember, we only had one rain event right at the tail end of bloom."
The latest blooming blocks were the worst affected. He had some fireblight in all his varieties this year, but it was most severe in Bosc and Concorde.
In a three-acre, 18-year-old Bosc block, which had never had fireblight before, the crop was shaping up to be the best ever, but didn't make it to the warehouse.
Some of the trees, which were trained to a modified vertical axis system, had as many as 20 to 30 fireblight strikes in them, so Prey made the decision right away to cut them back to a stump and regrow them with four leaders from each trunk and train them to a V system, which he prefers. He will regrow the trees and save the expense of replanting. "I think if you come back in four years, they'll be producing well again," he said. "The root system is healthy and established."
Now, he realizes he should have done the same thing in the Concorde block that was so badly hit. A 20-person crew spent the month of June going through the orchard looking for strikes and cutting them out, but were never able to get ahead of the disease in the Concordes.
"Knowing what I know now, I would have made stumps out of all these and saved all the root systems," he said. "First of all, it would have saved me going through the orchard ten times to look for fireblight. It would have saved me a lot of time. For those few trees and pears I saved, it wasn't worth it. Many of those trees we cut two, three, or four times, then lost them anyway."
Just to illustrate the variety's extreme sensitivity, he points out that in two pollinizer rows of Red Crimson, which also is very susceptible to the disease, he successfully cut out the fireblight strikes. "You go through that row now and you won't find any blight," he said.
Prey faces a tough choice this fall. He could grow back the Concorde trees from the stumps, but he's afraid that they might succumb to fireblight again in a year or two. He could cut all the trees back to the stump and graft them over to a different variety, but it's possible that the fireblight has moved down the trunks to the roots in some of the trees. Or he could just pull out the whole block and replant.
Gerald Green of Tonasket, Washington, has gone through a similar experience to Prey's. He lost half his Concorde trees to fireblight this year and is removing his nine-year-old, eight-acre block.
Green said the trees, which were on Old Home by Farmingdale 97 rootstock, produced large fruit and generated good returns, but he's been battling fireblight ever since he planted the block. This year, the fireblight was fatal.
"I tried taking out the limbs, but that didn't work, so I took out approximately 50 percent of the trees, and the other 50 percent will come out this fall," he said.
The fireblight has spread to an adjacent Bartlett block, but he should be able to save those trees.
Randy Smith of Cashmere, Washington, had a small Concorde block that had no fireblight in it until one year when the trees were about ten years old. "It seems like all of the stars were aligned negatively, and I got this infection," he recalled.
"My fieldman got it as early as he could, and we struggled the entire year trying to get ahead of it through cutting, and never could. The following year, I ended up removing the entire block. It was just decimated.
"What I found in the process is that the only way to possibly get ahead, in my estimation, is if you see one sprig of fireblight in the tree, you remove the tree immediately. We cut several feet ahead of what we saw, and the infection was there. It was an amazing thing to see."
Smith said it was particularly galling to have spent ten years growing a beautiful block of trees, only to lose the whole thing in one year. "That's the heartbreak of it," he said. He liked the variety because of its good eating quality, and the returns were good, he said. "It was a nice alternative, and that's one of the things that drew me to it. If it had proven itself out, I potentially would have expanded and done more, but that kick I got in the stomach I got from fireblight made me step back and say, 'I don't need this agony.'"
Tim Smith, Washington State University Extension educator for north central Washington, said he's beginning to think that when the fireblight bacteria get into a Concorde tree, the disease becomes systemic. "It doesn't attack the tree and then move in. It moves in and then attacks the tree," he said. "It shows up on the trunk first and then moves out very rapidly."
Dick Kerr of Omak, Washington, who has a10-acre block of Concorde planted in 2000 and 2001, said fireblight is a huge concern. "Fireblight scares me to death," he told fellow members from the Chelan Fruit, Inc., cooperative when they visited his orchard last summer. "I've seen my friends battle that and lose their orchards."
Kerr said he's had fireblight show up in the trees when there's been no bloom in the orchard for two months. He's found oozing infections on branches where they were punctured by the nails of limb spreaders. He said there's no answer but to keep on top of the fireblight sprays. He applies eight per season and has cut back on irrigation and fertilizer to minimize the trees' susceptibility.
Kerr said he's not unhappy with the returns on Concorde, but after paying for his fireblight sprays, there's not much profit left, and he worries that if there is not much production of Concorde, it will be difficult to maintain a market.