Impact of the Red Pine Shoot Moth, Dioryctria resinosella (Lepidoptera: Pyralidae), on Height and Radial Growth in Wisconsin Red Pine Plantations

A newly described species, the red pine shoot moth, Dioryctria resinosella Mutuura, was found to be responsible for a decline in form of Pinus resinosa Ait. in central Wisconsin. Larval shoot feeding resulted in height and radial growth losses. Height growth losses were evaluated by comparison of growth in epidemic years with potential growth determined by a biological growth curve equation. Radial growth losses were evaluated by comparison of pre-outbreak growth to growth in outbreak years. Height growth loss estimates for various stands ranged from 38 to 65% over a 9-year epidemic period. Radial growth loss estimates ranged from 16 to 42% in the same stands over the same period.