Systemic control of Nantucket pine tip moth (rhyacionia frustrana scudder in Comstock, 1880) enhances seedling vigor, plantation establishment, and early stand-level productivity in Pinus taeda L

Abstract

Establishment is a vulnerable and expensive stage of stand development in intensively managed pine plantations. We evaluated the capacity of establishing loblolly pine (Pinus taeda L.) plantations to increase productivity by systemic control of Nantucket pine tip moth (Rhyacionia frustrana Scudder in Comstock, 1880). In January 2009, four genotypes of improved genetics loblolly pine were planted in whole-plot treatments of herbaceous competition control at an upper coastal plain (UCP) site and phosphorus fertilization at a lower coastal plain (LCP) site, and split-plot treatments of tip moth control. Trees were monitored for tip moth infestation levels, vigor, survival, and stand-level biomass production for 2 years. During this time, tip moth infestation levels were very high at both sites, averaging 69% at UCP and 70% at LCP. However, levels averaged only 8% at UCP and 39% at LCP in treatments that included applications of systemic insecticides at planting. At LCP, biomass production averaged 2,159 kg ha-1 after 2 years. Protection from tip moth increased LCP biomass by 11% averaged across genotypes and 20-30% for the most responsive genotypes. At UCP, 2-year pine biomass production was much lower at 114.5 kg ha-1 and was increased 150% by protection from tip moth. At UCP, there was a strong effect of genetics whereby one genotype experienced very high mortality (mean of 30%) attributed to meteorological conditions of the establishment year; however, this was greatly decreased (17%) by protection from the interacting stress of tip moth damage. We conclude that systemic control of tip moth using imidacloprid soil tablets has the potential to greatly enhance pine plantation establishment success and early productivity in areas of heavy pest pressure, which may compound through stand development. © 2014 Society of American Foresters.