Resistance of polyamide and polyethylene cable sheathings to termites in Australia, Thailand, USA, Malaysia and Japan: A comparison of four field assessment methods

Cables sheathed with medium density polyethylene or polyamide were exposed together with highly palatable bait wood to termite faunas in south-eastern and northern Australia, Thailand and southern USA using three methods: below-ground exposure, samples buried horizontally at a depth of 15–30 cm; graveyard method, samples inserted vertically 25 cm deep into the ground; ground contact method, samples placed horizontally on the ground surface, covered with soil and a plastic sheet. Samples were inspected for damage and bait wood replaced annually for six years. No polyamide sample was attacked. Damage to polyethylene was most severe at the Australian sites (across all methods) and in the graveyard method (across all sites), although in Australia in the below-ground method samples experienced greatest damage. Exposing samples together with bait wood within containers for one year, and replenishing bait wood up to three times, i.e. an ‘accelerated’ test method, compared to the standard procedure of providing new bait wood only once a year, resulted in only very limited damage to cables at Asian sites (Macrotermitinae, Coptotermes spp., Malaysia; Coptotermes formosanus, Japan), matching the earlier results for Thailand. But 73% of samples were destroyed by Coptotermes acinaciformis in northern Australia. The Australian termite fauna responds more aggressively to plastic samples than major pest species of termite elsewhere.

► After 6 years and using 3 methods no polyamide (Nylon 12) sample was attacked.
► Damage to polyethylene most severe in Australia, mainly by Coptotermes acinaciformis.
► Coptotermes formosanus and C. gestroi, global pest species, caused hardly any damage.
► 4th method (1 year, containers): many samples destroyed in Australia.
► Only very limited damage to cables by termites at Asian sites.