Ambrosia beetle damage trees

Ambrosia beetles belong to a specialized group of wood boring insects that tunnel into the sapwood of trees to lay eggs and cultivate a particular fungus. The adults and the young that hatch feed on this fungus. When the adults are boring through the tree, they push out a long stand of sawdust that looks like a toothpick coming out the base of the tree. These little toothpick-like protrusions are a sure sign that the tree is under attack from ambrosia beetles. This boring damage and contamination by the fungus and other diseases that might enter the tree can eventually kill the host.

Toothpick like strand resulting from the Ambrosia beetle boring

Credit: umd.edu

The Asian ambrosia beetle (Xylosandrus crassiusculus) is of particular importance to local nurseries and landscapers because it has been shown to infest and kill trees such as flowering cherry, redbud, red and sugar maple, katsura, persimmon, and pecan. The Asian ambrosia also has economical impact in the Gulf States where it impacts pecan growers. The Asian ambrosia beetle was first spotted in South Carolina in 1974 and it has spread into the Southeast and Gulf States, including Frederick County. The ambrosia beetle becomes active in early spring once the first mild spell hits; their numbers can be estimated using traps. Recent reports by the University of MD Extension Department indicate that ambrosia beetles are being trapped at 5 times the numbers of last year. Asian ambrosia beetles normally attack damaged or stressed trees, but they also can attack seemingly healthy individuals. Typically the healthy trees that are attacked are those that are growing in a nursery or have been transplanted less than 5 years. Once these beetles enter the tree, it is hard to get rid of them. The best defense is to keep your landscape trees healthy and remove and destroy trees that have been killed by these beetles. Another strategy is to employ insecticides as a preventative measure by spraying the base of susceptible trees with an insecticide that is registered for use on ambrosia beetles.

Article by FCFCDB

Nature Notes for 6/30/2013