The granulate ambrosia beetle, Xylosandrus crassiusculus, is the primary ambrosia beetle pest of nurseries in the Southeast. Today we found a similar ambrosia beetle species – the first of the season – in our traps at the NCSU Lake Wheeler Research Station in Raleigh.
The beetle we found was Xyleborinus saxeseni which is commonly called the fruit tree pinhole borer. This species is also a pest of nursery trees and usually becomes active before granulate ambrosia beetles. However, with the warm weather we’ve had the full suite of ambrosia beetles will be out soon. It is time to protect trees if you haven’t started already. Spray susceptible trees with permethrin every three weeks or so. Ambrosia beetles damage many deciduous tree species and prefer dogwood, redbud, styrax, magnolia, cherry, Japanese maple, and others. You can find more in a free nursery production guide (available as an iBook) and in an article I wrote for American Nurseryman. Although it is time to spray (at least in Raleigh) it is not time for irrigation. We have found that over-watering makes trees more susceptible to ambrosia beetle attacks.