The appearance of little cherry diseases calls for aggressive action, says Dr. Ken Eastwell, plant pathologist for Washington State University.

“When it comes to little cherry diseases, inaction is not an answer,” he said, adding that the disease can spread from infected trees to adjacent trees and ­neighboring orchards, causing severe economic impact.

How fast the disease spreads depends on the level of disease management.

“You need to remove trees as soon as you see symptoms, keeping them contained as they’re taken out of the orchard,” he warned. “If infected trees are left in the orchard, disease incidence increases greatly.”

He advises growers, when roguing trees, to kill vectors infesting the diseased trees so they are not spread throughout the orchard as trees are removed. Spray diseased trees with the appropriate insecticide seven days before cutting them down.

Eastwell offered the following suggestions for ­managing little cherry disease:

Little cherry virus 2

  1. Plant only virus-free trees, including ­pollinators.
  2. Remove symptomatic trees, being wary of root grafting, and replant with clean stock. (Remove entire orchard if more than 10 percent trees are infected).
  3. Take care when removing trees to avoid ­spreading vectors throughout orchard.
  4. When replanting, remove bitter cherry plants near the orchard.
  5. Control apple and grape mealybug vectors in orchard.

Little cherry virus 1

  1. Plant only virus-free trees, including ­pollinators.
  2. Rogue infected trees based on economic impact.
  3. No vector has been identified.

Western X phytoplasma

  1. Plant only virus-free trees, including ­pollinators.
  2. Manage nearby ornamental hosts of chokecherry and bitter cherry, removing or treating with insecticide.
  3. Treat orchard for leafhopper vectors, using delayed dormant oil sprays and insect control until leaf drop.
  4. Control weeds that harbor leafhoppers and ­phytoplasma.