From late summer through early November, the N.C. Forest Services’ Forest Health staff, the Plant Industry Division, and cooperators with the Duke Forest set and monitored 104 traps across the state with the intent of detecting the walnut twig beetle in new locations. This beetle is the carrier for a fungus (Geosmithia morbida) that causes thousand cankers disease. It is native to Southwestern U.S. and Mexico and to date, has only been found in one county in North Carolina — Haywood County. The disease affects black walnut and butternut trees and kills trees two to three years after symptoms appear.
The traps used are funnel traps with a lure to attract the beetle. When the small beetles (and other insects) fly into the trap, they fall down through the series of funnels into a cup at the bottom containing a killing/preservative solution. Every two weeks, the traps are checked and catches collected and screened.
Several traps were threatened this year by Hurricane Matthew floodwaters in the east and wildfires in the west, but most of the traps survived. Screening was completed in mid-December and no walnut twig beetle was found in any of the traps.
What does this mean for our state? There will be no new quarantines enacted for the state at this time. Haywood County remains the only county under quarantine for this pest, meaning walnut and butternut material and all hardwood firewood cannot leave the non-quarantined zone without a compliance agreement with the Plant Industry Division. Virginia and Tennessee also have multiple confirmed locations of the disease as well, so there is introduction potential from both the west and north. The Invasive Pests in North Carolina map shows the locations of several pests currently being monitored along the East Coast.
North Carolinians are doing a great job keeping this pest contained to a small area. Remember to buy firewood locally and burn locally. Moving firewood is the easiest method of moving this disease and many other pests to new areas in our state.