Q. Have lost several young cherry trees. Problem seems to be boreres that stress the trees – evidence of sap seeping out of possible entry wounds. Can a systemis insecticide be used? If not, what? John Delaney – Puyallup, WA
A. I have Peach Tree Borers on my cherries this year as well. The sap you see oozing is the trees defense mechanism. When the trees are healthy and well watered the oozing of sap often flushes out the borers. You can also help by taking a thin but strong wire and inserting it into the hole through the sap “skewering” the borer. Systemic insecticides are not recommended on cherries used for consumption since the insecticide will be present in the fruit. Moths lay eggs on the trees and their larvae are the borers. Commercial growers use pheromone traps to catch the adult moths and time their sprays once the eggs are laid. Once the larvae (borers) hatch from the eggs they can be sprayed. But once they bore into the tree external sprays cannot control them. This makes timing critical. Skewering is the best control for the home gardener. Bud break is the time to start looking for the borers.