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Pest Status
Background
Chapter 58
Neodiprion sertifer (Geoffroy), European
Pine Sawfly (Hymenoptera: Diprionidae)
K.J. GRIFFITHS, J.e. CUNNINGHAM and I.S. OTVOS
The European pine sawfly, Neodiprion serlifer (Geoffr.), was first recorded in North
America in New Jersey in 1925 (Schaffner 1939) and in Canada near Windsor, Ontario,
in 1939 (Raizenne 1957). In Ontario it dispersed steadily until, by 1968, it was found
throughout Ontario south and west of a line from Victoria Harbour to Belleville (Fig. 17).
Transport of infested nursery stock resulted in isolated populations of N. serlifer well
beyond this area - on Manitoulin Island, first recorded in 1966 (Sippell el al. 1966) and
in Sault Ste. Marie and North Bay, first recorded in 1968 (Sippell el al. 1969).
In the decade since 1968 the area occupied by N. serlifer has continued to expand,
moving slightly to the north near Georgian Bay, but mainly to the east along the St.
Lawrence River, until by 1978 the continuous distribution extended almost to the
Quebec border along the St. Lawrence and as far north as Ottawa (Fig. 17) (Lindquist &
Miller 1979).
The isolated infestations on Manitoulin Island and at Sault Ste. Marie continued
throughout the period 1968-78, but no N. senifer have been found in North Bay since
1969. N. sertifer larvae were collected for the first time at several locations in Ottawa in
1969 and by 1973 they were also found in the surrounding areas. They apparently
remained there as Ottawa is now in an area of continuous distribution. An isolated light
infestation was found north of Thessalon, Ontario, in 1974. The area was treated from
the ground with nuclear polyhedrosis virus (NPV) in 1975 and 1976, and there have been
no further recoveries of N. serliler.
In 1970 there were several heavy infestations in southwestern Ontario, where the
insect has been present the longest. Infestations causing moderate to severe defoliation
continued in this area until 1972. A decrease in numbers was noted in 1973, and this
decrease continued until by 1977 generally low populations were recorded throughout
the area.
In 1974 N. sertiler was recorded for the first time in Canada beyond the borders of
Ontario. A single colony was recovered from Scots pine, Pinus sylvestris L., in Charlesbourg,
Quebec, a few kilometres northeast of Quebec City (Martineau & Lavallee 1975), and a
few colonies were recovered from Scots pine at Windsor Lake near St. John's, Newfoundland
(Clark & Singh 1975). No further recoveries were made in Quebec, but N. serlifer
has persisted and spread in Newfoundland. It was reported on ornamental pines Pinus
spp. and in the few pine plantations within a radius of 15 km of St. lohn's by Otvos &
Griffiths (1979). It was established by rearing some larvae that no parasitoids were
present. The first discovery of N. serlifer in Nova Scotia was made in 1980, when it was
obtained from ornamental pines at Little Harbour, Pictou County, and Truro, Colchester
County (Magasi 1981).
Studies of the population dynamics of N. sertifer carried out at the Great Lakes Forest
Research Centre, Sault Ste. Marie, Ontario, had started in 1960 and were continued until
1972. An overview of this work is given in Lyons el al. (1971) and Lyons (1977a). In
brief, outbreaks in southern Ontario typically occur in young plantations where few
natural control agents are present. Density peaks in 4-6 years, then declines to a low
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