Effects of a Commercial Chitosan Formulation on Bark Beetle (Coleoptera: Curculionidae} Resistance Parameters in Loblolly Pine1

J. Entomol. Sci. 46(2): 124-134 (April2011) Abstract A commercially available chitosan product, BeyondTM, was evaluated for its effects on loblolly pine, Pinus taeda L., responses believed related to bark beetle resistance. Treatments were applied 4 times at approx. 6-wk intervals between May and November 2008. Five treatments were evaluated: ground application (soil drench), foliar application, ground and foliar applications combined, water-only (soil drench), and untreated. Two response variables were measured: yield of oleoresin accumulated at 48 h from wounds inflicted at breast height (5 sample periods) and area of lesion formed in response to inoculation with Ophiostoma minus (Hedgcock) Sydow & P. Sydow (2 sample periods). One treatment, ground application of Beyond, resulted in a significant increase in oleoresin yield (about 40% experiment-wide). Foliar treatment alone, or combined with ground application, did not result in a significant change in oleoresin yield. None of the treatments resulted in a difference in lesion area produced in response to inoculation with 0. minus. In summary, application of a commercially-prepared chitosan formulation to loblolly pine produced inconsistent responses in tree parameters associated with bark beetle resistance, suggesting that exogenously applied chitosan preparations have limited utility for managing bark beetles.