Rise and Fall of Red Oak Borer (coleoptera: Cerambycidae) in the Ozark Mountains of Arkansas, Usa

Oak-hickory forests of the Arkansas Ozarks recently incurred extensive tree mortality due in part to a native wood-boring beetle, the red oak borer Enaphalodes rufulus (Haldeman) (Coleoptera: Cerambycidae). Historically, red oak borer has existed throughout southeastern U.S. forests at relatively low population levels, but Arkansas infestation estimates in 2001 and 2003 reported much higher populations. Red oak borer has a two-year generation with adult emergence occurring synchronously only in odd numbered years. We report here results of whole-tree estimates of pre-emergent red oak borer population numbers from 7 stands in 2005 and 3 stands in 2003 and 2007 in the Ozark National Forest. Trees were felled at each sampling site, cut into 0.5 m sections, split on site with hydraulic log splitters, and a count of live red oak borers was recorded for each tree. In 2001 and 2003, red oak borer population estimates indicated emerging populations much higher than any previously reported. An exponential decrease during a single cohort between 2003 and 2005, and even lower populations in 2007 suggest that red oak borer populations have returned to historic densities.