Forest Insect and Disease Survey; Ontario, 1965 - NFIS

13 35
TABLE. 17
Summary of Infestations of the Yellow-headed Spruce Sawfly
at Eight Points in the Lake Huron District
from 1963 to 1965
Note: Counts were based on the examination of 100 white spruce trees at each point.
Tract Township
Rennie Euphrasia
Rocklyn Euphrasia
Riddell Bentinck
Crawford Bentinck
Main Glenelg
Kenny Glenelg
Minto Minto
Victory Arthur
Per cent of
Degree of
trees infested
infestation
1963 1964 1965 in 1965
68 75 60
54 15 8
40 90 95 M
14 50 62 L
35 75 50 L
42 35 52 L
20 16 4 L
4 4 0 L
White-pine Weevil, Pissodes strobi Peck.
Moderate to high incidence of weevil damage was noted at several locations in the
district in 1965. Twenty to 40 per cent leader damage occurred in parts of the Riddell
Tract, Bentinck Township. The incidence of attack increased from 20 per cent in 1964
to 25 per cent in 1965 in a small section of the Grey Main Tract, Glenelg Township,
and from five to 15 per cent in the Moir Tract, Culross Township, general increase
in leader damage occurred in several white pine plantations in the southern part of
Bruce County. Light damage was noted in the Galt and Guelph areas.
Counts made to determine the degree of infestation at two sample points are
summarized in Table 18,
TABLE 18
Summary of Shoot Damage by the White-pine Weevil in Plantations
at Two Points in the Lake Huron District
from 1963 to 1965
Note; Counts were based on the examination of 100 trees at each point.
Location
townshi
...1111V
Av. d.b.h. of sample
trees in inches
Per cent of trees
infested
196 16.; 1965
.01,1MIOMMIIMM12.1■11■0M.
Per cent of trees
infested all
ears
Brant
private
plantation
Culross
Moir Tract
5
4
7 3 4 63
2 5 15 17