In this laboratory evaluation, radiata pine wood blocks (50 x 25 x 15 mm3) were impregnated with fipronil (a phenyl pyrazole) at various concentrations (0, 5, 10, 20, 40, 80, 100 and 200 ppm). Half the treated blocks underwent a leaching schedule for 5 days, while the remainder were unleached after treatment. Five replicates per treatment regime were presented to the test termite, Coptotermes acinaciformis, and the amount of wood consumed and termite mortality recorded over 8 weeks. Fipronil was toxic at all concentrations and deterred feeding by the foraging termites in both leached and unleached treatment regimes. After 8 weeks, 90 per cent of the termites at the 5 and 10 ppm treatments were dead. Mass loss of the treated specimens in laboratory bioassays is a most important criterion for the assessment of a potential wood preservative. Here, in both the leached and unleached treatments, no mass loss was recorded at retentions of 0.005 kg/m3 and above. At a retention of 0.002 kg/m3, mass losses were 1.18% and 3.5% for unleached and leached specimens respectively. The results indicated that fipronil has termiticidal action, and probably acts as a contact poison at the levels tested. Mould growth on the treated wood specimens was an indication that fipronil was not a mould inhibitor.

Download document (117 kb)
free for the members of IRG. Available if purchased.

Purchase this document