By Louise Thomas

The Forest Research Institute has beaten overseas competitors to win a contract that will use genetic engineering to fight a moth that is decimating Chilean forests.

The three-year contract from Fundacion Chile, a Government organisation, is worth more than $500,000.

The New Zealand scientists will use advanced genetic techniques to engineer a variant of radiata pine that is resistant to the pine shoot tip moth, Rhyacionia buoliana, which moved into Chile's 1,700,000ha radiata pine estate in 1985.

The moth lays its eggs in pine shoots, where the larvae damage the stem tips, causing loss of the main stem and stem malformation. Infected trees are often rendered useless for lumber.

The moth is not found in New Zealand, but Forest Research's principal scientist, Dr Mike Carson, says the threat to our own industry from the pest is real.

Work on the contract has already begun. A shipment of Chilean green pinecones has yielded a crop of embryonic tissue that the scientists team are in the process of genetically modifying.

Trials involving the moth will be done in Chile so there is no danger of the insect spreading to New Zealand.

The contract will also involve testing a gene modified with the pesticide Bt-toxin to see if it will kill the moth.

Bt-toxin recently hit the headlines after maize genetically modified to produce it was found to harm monarch butterflies. However, some scientists have questioned the finding, saying the high concentration of pollen used in the experiments does not occur in nature.

A scientist working on the project, Dr Christian Walter, says the Chileans looked at other control options, such as spraying, but these were either ineffective, expensive, or unacceptable to the public.

"One option to control insects feeding on the trees is to spray the area with pesticide such as the Bt-toxin. But aerial spraying is cost-intensive and not always publicly accepted. The expression of a gene for the same toxin in the plant would achieve the same effect, and would be much more cost-efficient."

When genetic transformation of the pine embryonic tissue has been completed, the resulting new plantlets will be tested in controlled environments in New Zealand to confirm that genetic modification has taken place.

Feeding trials, using an insect related to the moth but already present in New Zealand, will be carried out at HortResearch in Auckland to confirm the plantlets are toxic.

The plantlets will be shipped to Chile for field trials, probably within 18 months.

Chile will undertake controlled feeding trials of the new pines in a contained glasshouse environment, where the seedlings will be exposed to the moths.

If the trials succeed, Chile will use the new pine gene to develop a replacement for its ailing radiata pine.