Bifenthrin treatment for balsa: Susceptibility of Papua New Guinea-grown 2 Ochroma pyramidale to attack by Coptotermes acinaciformis (Blattodea: 3 Rhinotermitidae) in an Australian context

This study evaluated the termite susceptibility of Papua New Guinea (PNG) balsa (Ochroma pyramidale) against Australia’s most economically important wood-destroying termite species, Coptotermes acinaciformis. Samples of envelope treated PNG balsa with the insecticide bifenthrin and non-treated balsa, radiata pine (Pinus radiata) sapwood and southern blue gum (Eucalyptus globulus) heartwood were exposed to seven different colonies of C. acinaciformis at a field site in the Northern Territory, Australia. The results indicated that balsa is susceptible to termite attack, with a mean mass loss of 30.9 % (range 3.8 – 99.9 %). Mean mass losses for radiata pine and southern blue gum were 90.3 and 98.9 % respectively. It was evident that balsa can be successfully protected from termite attack with envelope-treatments of bifenthrin, with the latter proving to be highly efficacious at mass/volume retentions much lower than those specified in AS 1604.1 and typically used in the Australian timber preservation industry.