pdf, 57.71Mb - Entomological Society of Canada
pdf, 57.71Mb - Entomological Society of Canada
pdf, 57.71Mb - Entomological Society of Canada
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Ontario<br />
Gilpitlia Ill'rcylliae (Hartig), 297<br />
The insect has been sporadically reported, and occurs throughout the province within<br />
its known range but usually in very low numbers. In 1977, light defoliation <strong>of</strong> white<br />
spruce occurred in parts <strong>of</strong> southwestern Ontario.<br />
The Forest Insect and Disease Survey participated in a parasitoid identification<br />
project with CIBC in 1973. Of 160 sawfly cocoons, 7 adults <strong>of</strong> E. vellicatus emerged<br />
(4.4% parasitism); the parasitoids were mostly male.<br />
Manitoba<br />
Evaluation <strong>of</strong> Control Attempts<br />
Literature Cited<br />
The insect was first reported in Manitoba in 1969, when it was found in low<br />
populations on 5200 km! adjacent to the Ontario border. In 1970, populations were<br />
reported on a further 2600 kml, as far north as Otter Falls and Meditation Lake in the<br />
Whiteshell Provincial Park, and as far west as the Agassiz and the Sandilands Provincial<br />
Forests. It has not extended its range since then and population levels have remained<br />
low.<br />
The European spruce sawfly appears to be controlled, largely by biological agents.<br />
However, there may be differences in areas that are regularly subjected to chemical<br />
sprays. Neilson et al. (1971) stated that when spraying stopped, there was a sharp<br />
increase in sawfly populations - at least until the balance between host and control<br />
agent was re-established. This phenomenon was observed again in the 19705. In each<br />
case, the spray period lasted only 2-4 years. It is not known what is happening in areas<br />
<strong>of</strong> sustained chemical insecticide application: the European spruce sawfly, obviously,<br />
is kept at low populations but possibly not by biological control agents. Nor is it known<br />
what the status <strong>of</strong> these agents is or if they would rapidly re-establish the balance<br />
necessary for control once chemical insecticide spraying ceased. High-value spruce<br />
plantations, which were practically non-existent in the 1930s and 194Os, are now<br />
plentiful and provide a bountiful food supply for the sawfly.<br />
Neilson, M.M.; Martinez. R.; Rose, A.H. (1971) Diprion hercyniae (Hartig), European spruce sawfly. In: Biological control programmes<br />
against insects and weeds in <strong>Canada</strong>. 1959-1968. Commonweahh /outilUle <strong>of</strong> Biological Control Technical<br />
Communication 4,136-143.
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