Campus cherry trees to be treated for pest Oct. 4

A local landscape pest management and tree care company will treat nearly 80 cherry trees on the Capitol Campus Oct. 4 for control of cherry bark tortrix, an invasive insect.

This application is a seasonal follow-up to treatment done last spring.

Wolberts Inc. will use a low-pressure hose and gun to apply a pesticide to the entire trunk of each tree, from the soil up, and the lower scaffold branches if there is evidence of the beetle found there. There will be no spraying of the tree canopies.

The work will be done between 6 a.m. and 7:30 a.m., but is weather dependent. The spraying will be delayed until Saturday, Oct. 5 or Monday, Oct. 7 if there is more than a light rain or there is enough wind to cause the pesticide to drift from the treated areas.

The pesticide that will be used is almost non-toxic to humans, causes nearly no allergic side effects and is not a skin or eye irritant, according to toxicologists and the Environmental Protection Agency. All areas sprayed will be flagged with treatment signs, in accordance with state law.

The goal of the spraying is to reduce the infestation on campus, not to eradicate it, which is very difficult to do.

The cherry bark tortrix is a non-native moth that damages the bark and inner layers of a tree, according to Washington State University researchers. It can kill trees or leave them susceptible to disease and other insect problems. The moth, first discovered in Washington in 1991, attacks most tree fruits, not just edible and ornamental cherries.

Below is the list of trees to be treated:

  • 8 - Colony cherries on the North Diagonal
  • 2 - Fuji cherries by the Vietnam Memorial
  • 27 - Kwanzan cherries on Cherry Lane
  • 1 - Kwanzan cherry at the Museum
  • 1 - Kwanzan cherry at the Governor's Mansion
  • 1 - Ferrill crabapple west of the Temple of Justice
  • 1 - Flowering plum at the Visitor Center
  • 31 - Yoshino cherries at O'Brien/Cherberg buildings
  • 5 - Asian cherries at the Archives building

Spraying the trees is consistent with integrated pest management practices, which call for chemicals to be used only as a last resort. In the case of controlling cherry bark tortrix, there is no effective alternative to the use of chemical pesticides and the trees may die if not treated.

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