The 2012 ASHS Annual Conference

For the past 30 years, North and South Americas, Europe, and Asia have experienced an increased loss of landscape and forest pines due to pine wilt disease. Pine wilt is a fatal disease caused by the pinewood nematode (Bursaphelenchus xylophilus) and its vector, the pine sawyer beetle (Monochamus spp.). The objective of this study was to determine if southern pine sawyer beetle (Monochamus titillator; SPSB) feeding preference could partially explain tree species susceptibility to pine wilt and provide non-preferred pine species alternatives for the landscape. Choice and no-choice feeding preferences of SPSB were evaluated using four species of pine as a preliminary investigation to determine the potential of pine wilt tolerant/resistant pine species. In May and June of 2011, one, newly emerged beetle (less than 24 hrs. old) was placed into each 90 L feeding arena containing one shoot of current season growth for four pine species (Pinus sylvestris, Scots; P. ponderosa, ponderosa; P. strobiformis, southwestern white; and P. taeda, loblolly) for the choice study and only one shoot southwestern white pine for the no-choice study. Shoot samples were fed on for 48 hrs. and assessed for feeding site area and feeding area percent [(feeding site area ÷ total shoot surface area) × 100] using a leaf area scanner system (WinFolia, Regent Instruments Inc., Ottawa, Ontario). Choice feeding area and percent feeding data revealed that Scots, ponderosa, and loblolly pines were preferred feeding hosts for SPSB while southwestern white pine was not preferred. However, no-choice feeding area and percent feeding data did measure feeding on southwestern white pine. No-choice feeding indicated that while southwestern white pine was not a preferred feeding host for SPSB in choice feeding tests and when faced to starve or subsist by feeding on a non-preferred species, non-preferential feeding may occur and potentially spread pine wilt. The preliminary results from both the choice and no-choice studies will be used for further evaluations determining pinewood nematode susceptibility of evaluated pines to pine wilt. Further investigations to assess pine sawyer beetle feeding preferences and pinewood nematode pathogenicity may result in identifying pine wilt tolerant/resistant pines or other conifer selections for use as windbreaks, forestry, and/or landscape use.