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FPL 12 - Larch Sawfly

The information accessed from this screen is based on the publication: Erickson, R. D. 1984. Larch Sawfly. Forestry Canada, Forest Insect and Disease Survey, Forest Pest Leaflet No. 12 4p.

Introduction

The larch sawfly, Pristiphora erichsonii (Hartig) (Hymenoptera: Tenthredinidae), was first noted in British Columbia north of Fernie in 1930. Since that time, it has been observed over the range of western larch in the southeastern portion of the province. It was first seen on eastern larch west of Fort Nelson in 1952.

This sawfly was epidemic on western larch during the 1940s and again became epidemic on the same host in 1964. Annually during 1965 to 1967, 130 000 to 150 000 ha of western larch in southeastern B. C. were moderately to severely defoliated. Light to moderate infestations were observed in eastern larch in Prince George Region during 1962 to 1965.

In 1976 a new outbreak developed in the Nelson Region, when 4 ha near Sparwood were lightly defoliated. This expanded to 800 ha in the Elk River Valley in 1977 and to 4 600 ha of light to severe defoliation in 1978. By 1981 only localized areas of light defoliation occurred, but in 1982 a new outbreak severely defoliated western larch stands totalling 12 000 ha from the Elk River Valley to Dutch Creek.

For more information, see the Larch Sawfly Forest Pest Leaflet in the Canadian Forest Service bookstore.