Some trees in California are becoming so weak that they are toppling over. Other trees are now literally filled with jelly, their insides are completely digested. These trees and countless others have become victims of a new pest to our area; the “polyphagous shot hole borer”.
The polyphagous shot hole borer is a type of ambrosia beetle. The female of this species is black in color, the male is brown and both are smaller than a sesame seed (0.1 inch in length).
These pests do not eat wood. Instead, they drill circular tunnels toward the heart of the tree. They carry fungal spores in their mouths and sow them like seeds as they go. The larvae of the beetles will later harvest and feed on the fungus.
This fungus destroys the food and water conducting system of the tree, eventually causing stress and dieback. The Box Elder, Castor bean, Avocado, English Oak, California coast live oak, Big leaf maple, Liquidambar, Coral tree, Titoki tree, California sycamore and Blue Palo Verde, are just a few to be attacked by the polyphagous shot hole borer.
An entomologist at UC Riverside, Richard Stouthamer, used genetic analysis to trace the beetle’s origin to Vietnam. No one is sure of how the beetles made their way to the U.S..
Experts want to contain this invasive pest before it spreads throughout California. The beetles have already spread through Los Angeles, Orange and Riverside Counties.
At this time, there is no known treatment to eradicate this pest. Officials from the Department of Food and Agriculture, the California Avocado Commission, UC Riverside scientists and others gathered recently in Sacramento to review the latest intelligence and discuss how to deal with the problem.
