Orchards fight Little Cherry Disease

Dan Wheat

Capital Press

Kyle Mathison Orchards is just one of several orchards fighting Little Cherry Disease around Wenatchee, Wash. Tree removal and replanting is the main means of combat.

WENATCHEE, Wash. — Jaime Reyes, 36, has plenty to do as production manager of Kyle Mathison Orchards on Wenatchee’s Stemilt Hill, regarded as some of the best cherry growing ground in the world.

He oversees 26 crews of 25 pickers — that’s a small army of 650 people — picking 310 tons of cherries a day. They sweep through an orchard, several crews abreast, making an endless task go fast.

They were working their way up the hill in Sweetheart cherries on July 30 and approximately halfway through harvesting 8,500 tons from roughly 1,500 acres that will finish about Aug. 20 at the 3,600-foot level.

But in addition to all that, Reyes is on the front line of combating Little Cherry Disease.

The virus that results in small, bitter-tasting, unmarketable cherries has been increasing in the Wenatchee area in recent years.

Kyle Mathison Orchards tore out 160 acres of cherry trees last summer in the fight and replanted most of it this spring. Neighboring orchards took out 95 acres, Reyes said. One grower replanted apples and another is letting his ground lie fallow for awhile.

That’s all on Stemilt Hill, south of Wenatchee. Other growers engage the battle just north of town in Sunnyslope, near East Wenatchee’s Pangborn Memorial Airport and a little farther to the south in Rock Island and to the north in Orondo.

“Every year it’s more prevalent,” said Tim Smith, Washington State University Extension tree fruit specialist.

“The industry is getting more serious about it because it’s spreading, not getting better,” Smith said. “I’m concerned about it coming back into orchards after they’re replanted. There’s a lot of unanswered questions and it spreads more rapidly than any serious virus we’ve seen.”

Elizabeth Beers, entomologist at the WSU Tree Fruit Research and Extension Center in Wenatchee, heads a new three-year research project funded by Washington, Oregon and California to better understand and manage the virus. It’s known to spread by apple and grape mealy bugs and by roots.

On Stemilt Hill, Reyes indicated infected trees, marked with paint on their trunks, scattered throughout various blocks of orchard. The heavier concentration, where whole blocks have been removed, is up Stemilt Loop Road.

A 50-acre block of Sweetheart in the second year of fruiting and older Bing will be yanked by excavators, roots and all, on Oct. 1 and burned, Reyes said.

There’s no other way to combat root spread, he said. Mealy bug is fought with insecticide and that likely will mean the end of the orchard’s organic cherries, he said.

Trees show no symptoms until cherries reach straw color before ripening to red. Infected trees tend to lose leaves on their one-year-old wood.

Reyes has workers sanitize equipment when it is moved from block to block to try to prevent transport of mealy bugs. He said the virus doesn’t seem to attack Skeena but likes Sweetheart, Bing and Van and Black Republican used as pollinators.

Ground was fumigated between tree removal and replanting but the disease is returning on sprouts from old roots missed in tree removal, he said. Ground may need to lie fallow for three years, which would be a hit to production, he said.





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