Spruce budworm


Deepa Pureswaran: My name is Deepa Pureswaran, and I’m a research scientist with the Canadian Forest Service at the Laurentian Forestry Centre in Quebec City.

I’m a forest insect ecologist, and one of our projects involves studying the ecology and population dynamics of the spruce budworm, which is a major defoliator in Eastern Canada.

The spruce budworm is a defoliator; the larvae feed on the current year’s needles, the fresh needles that grow each year. And so the tree eventually doesn’t get to grow that year, and the needles fall off.

If there is defoliation over several years then the tree eventually dies from not being able to grow.

The spruce budworm is a native species that is always here and every thirty to thirty-five years it undergoes cyclical fluctuations in the population, and this is the beginning of a thirty-year cycle. The peak of the last outbreak was around 1975.

I’m working in collaboration with two other researchers at the Laurentian Forestry Centre, Jacques Régnière and Johanne Delisle, who have been working on the spruce budworm for the past three decades. And so they have a good monitoring system in place and also a lot of very nicely designed experiments to look, to see what the impact of parasitoids and predators are on the spruce budworm and how it changes at different population densities.

And so one of the experiments we are doing is we are looking to see when males fail to find females, at what population densities they can not find females anymore. And so we know, at the point at which the population might drive itself to extinction because males simply are not able to find female and mate with them.

It’s important to do this research so we can understand the ecology of the spruce budworm so that we can help forest managers implement management strategies more effectively.