Canadian Forest Service Publications

The epidemiology of the Swaine jack-pine sawfly, Neodiprion swainei Midd. 1970. McLeod, J.M. Forestry Chronicle 46(2): 126-133.

Year: 1970

Issued by: Laurentian Forestry Centre

Catalog ID: 15579

Language: English

Availability: PDF (request by e-mail)

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Neodiprion swainei, a defoliating sawfly specific to jack pine, has destroyed thousands of acres of commercially important jack-pine forests in recent years. This sawfly can kill trees within 4 years of the start of a population increase. Outbreaks are usually found in foci in poorer jack-pine sites on outwash plains, Tree mortality occurs after complete defoliation of the previous years' foliage, combined with severe defoliation of the current year's foliage. Tree mortality starts in the first year after particularly severe defoliation and may be cumulative to 5 years; thus, detection of the insect in a stand should warrant increased watchfulness.

Outbreaks may follow at intervals of about 8 years. Hazard areas for Quebec and Ontario are defined.