3 Oct 2012

'Electric' logs kill pests, researchers find

10:50 am on 3 October 2012

University of Canterbury researchers say they have made a breakthrough by using high voltage electricity to heat export logs and kill any pests they are carrying.

This is one of a number of research initiatives underway to find alternatives to using methyl bromide to fumigate logs and timber to kill insect pests and fungi.

Methyl bromide has been the standard pre-shipment treatment but there is been an international push to phase out its the use because it is an ozone depleting gas and poses human health risks.

The university's electric power engineering centre, Allan Miller says heat treatment using kilns or steam is accepted as a quarantine treatment for logs and timber being shipped to the USA and other countries, but using electricity is a new approach.

"We're trying to ... heat logs in order to kill the bugs," Dr Miller says.

"We're trying to do that by applying a high voltage to either end of the log: it's like a one-bar heater, and the current heats the log up and kills the bugs on it.

"We've tested a number of full-sized logs and have successfully managed to get them up to the temperature required to kill the bugs - just above 50 degrees Celsius.

"Then we've taken samples of the timber .. there doesn't appear to be any degradation".

Dr Miller says Canterbury University will be continuing the research over the next four years to refine the heating process to take it to a production level.

It is working with the Crown forestry research institute Scion, which will be using more than $5 million of Government funding to investigate a range of quarantine measures to reduce the market access risk for wood exports.

As well as electrical heat treatment, researchers are working on a cold sterilisation technique, using electron beams that convert electrical energy into x-rays to kill pests.