Improved Insect Virus Targeted To Prevent Forestry Losses

Currently, there is no effective means of controlling this pest, which attacks spruce and fir trees and is responsible for much of the damage to Canadian forests. But a research team led by U of G Prof. Peter Krell says a new viral defence against budworm could be ready for lab testing in a year.

"Clear cutting damage is minor compared to bug damage in any one year," says U of G Prof. Peter Krell, Department of Microbiology. "Having a strong virus that can adequately fight off the budworm is important to help preserve the forest habitat."

The spruce budworm infests trees and slowly kills them by eating the needles and new growth of trees. Trees may recover from budworm damage unless repeatedly attacked each year. In 1995 for example, 3.9 million hectares of Canadian forest were significantly damaged by spruce budworm, far outnumbering the losses from forest fires and logging. There are currently chemical pest controls available, but these insecticides carry environmental and health concerns. The use of viral control methods will alleviate these complications.

Increasing the virulence of the spruce budworm baculovirus -- a naturally occurring virus which attacks the spruce budworm -- is being tackled by Krell, graduate student Tammy Reid, and Basil Arif of Canadian Forestry Services in Sault Ste. Marie. This species-specific virus attacks only the spruce budworm and affects no other organisms, and leaves no undesirable traces.

"It is the ideal species-specific biological agent," says Krell.

However, the virus is not as strong as researchers would like to make a significant impact on the tree pests. So work on genetically modifying the virus to be more effective is being conducted. The researchers are developing a technique of adding the protein "fusolin," originally obtained from a different virus but now harvested in the lab, to improve the power of the spruce budworm baculovirus.

This baculovirus is ideal to work with, because viruses are natural organisms and do not pose the risks that other pest-control methods do, Krell says. The virus, even if genetically altered and with added fusolin protein, will leave no residue and will only attack the budworm, and no other creatures will be harmed.

The genetic manipulation of the spruce budworm baculovirus and fusolin-adding techniques could also be applied to other forestry and agriculture insect pests, by substituting a baculovirus that is specific to those pests.

When used in field trials, the virus preparation could be added to a substance that is attractive to insects, and then sprayed over the afflicted area, in the same manner that chemical pesticides are distributed.

This project was financed by the Natural Sciences and Engineering Research Council for the past three years. Preliminary laboratory studies will be completed in 1999.