Preferences of Coptotermes formosanus Shiraki and Coptotermes gestroi (Wasmann) (Blattodea: Rhinotermitidae) among Three Commercial Wood Species

The Formosan subterranean termite, Coptotermes formosanus Shiraki, and the Asian subterranean termite, Coptotermes gestroi (Wasmann), are both pests of wood in service in Hawaii and Florida. We conducted a laboratory study using method modified from those described in standard E1-09 of the American Wood Protection Association (AWPA 2009) to assess the termite resistance of three commercially available wood species used in regions of the USA where both termite species occur: Douglas fir, Pseudotsuga menziessii, southern yellow pine, Pinus spp. and redwood, Sequoia sempervirens. A multiple-choice (three-choice) assay was used for four weeks (28 days) in order to simulate field conditions of food choice and assess termite feeding preferences under 28 °C and 72-80% RH. 400 termites (360 workers: 40 soldiers) were released into each test jar. Five replicates and two controls of each wood species were used with each termite species. Termite mortality was recorded at the end of the test; and wood wafers were oven-dried and weighed before and after termite exposure to determine the mass loss due to termite feeding, and rated visually on a 0 (failure) to 10 (sound) scale. There were significant differences in mean mass loss values among the three wood species and between two termite species. The mean mass loss value for redwood was significantly lower than Douglas fir and southern yellow pine with both termite species. However, C. formosanus showed increased feeding on Douglas fir and southern yellow pine compared to C. gestroi.