No abstract

Regeneration pests of loblolly pine (Pinus taeda L.) threaten growth and survival in intensively managed loblolly pine plantations throughout the southeastern United States. The Nantucket pine tip moth, Rhyacionia frustrana (Comstock), in particular, often reduces growth of loblolly pine but has been difficult to control with traditional insecticides due to multiple annual generations and multi-year infestations which are difficult to predict in timing and location. Relatively new systemic insecticide products offer a solution in that their efficacy persists through multiple generations and years after a single application. Efficacy of systemic imidacloprid and fipronil were evaluated side by side across multiple sites in Virginia. Significant reductions in Nantucket pine tip moth damage were noted in trees treated with either the imidacloprid or fipronil product compared with check trees. After 2 yr, growth improvement of treated trees relative to controls was modest and not significant at all sites, but per acre volume indices were significantly greater in treated blocks as a result of higher tree survival. Reduced seedling mortality was attributed primarily to prevention of damage by pales weevil, Hylobius pales Herbst (Coleoptera: Curculionidae), by both insecticide treatments. Control of pales weevil in addition to pine tip moth suggests that systemic insecticide products with a long window of efficacy might control additional nontargeted pests.

Height, diameter, and survival of loblolly (Pinus taeda), longleaf (Pinus palustris), and slash (Pinus elliottii) pines in 16 plantations aged 2 through 7 yr were summarized for plots receiving herbaceous vegetation control treatments and for untreated check plots. Treatments tested at one or more sites included spot, banded, and broadcast herbicide applications for the first one or two growing seasons after planting. Analyses of variance and orthogonal contrasts were used to evaluate the effects of one or more of the following factors at each site: herbaceous vegetation control (treated vs. check); treatment duration (1 vs. 2 yr); and application method (band vs. broadcast or spot vs. band). Competition control had a significant positive effect on height and diameter at all 16 locations, and on survival or density where competition was most intense (5 of 14 sites). A second year of herbaceous vegetation control led to significant additional gains in height and diameter at 6 and 7 of the 10 locations, respectively, where those effects could be tested. Application technique had no significant influence on any pine attribute measured. South. J. Appl. For. 11(4):223-227.