Forest Insect and Disease Survey; Ontario, 1965 - NFIS

G 34
TABLE 13
Summary of Balsam-fir Mortality Caused by the Spruce Budworm
in Fort Frances District, 1961 to 1965
Location
Sturgeon Narrows
Sturgeon Lake
Cache Bay
Saganga Lake
Size of
plot
in acres
.20
Per cent Cumulative per cent
defoliation mortality by volume
1 •61 1 62 1.. 1 6 1'6 1961 1962 1963 196 196
57 15 2 0 0 23.2 46.3 58.1 66.3 71.5
87 26 9 7 2 11.1 36.4 68.0 75.5 86.0
Larch Casebearer, Coleophora laricella Hbn.
Populations of this casebearer have remained at a low level since first discovered
in the district in 1961, but an increase in distribution has been recorded each
year. In 1965 casebearers were found in Morson Township, 30 miles northwest of the
most westerly collection point in 1964. To date no casebearers have been found east
of Rainy Lake. Quantitative sampling was carried out at five points in Division 22
(Table 14).
TABLE 14
Summary of Larch Casebearer Larval counts in Fort Frances District
in 1964 and 1965
Note: Counts are based on examination of sixteen 18-inch branch tips, four from
each of four trees at each point.
Location
(township
Av. d.b.h.
in inches
Av. no. of larvae per
18-inch branch tip
196 196
Potts Miscampbell
Dobie
Crozier
Morley
3
2
2
2
2
1.0
0.2
0.1
0.6
0.1
0.6
0.6
0.1
0.2
European Spruce Sawfly, Diprion hercyniae (Htg.)
Populations of this spruce defoliator were at a low ebb in 1965. Although
two generations occur each year in the district and host trees were examined at
many points during both generations, a total of only nine larvae were found.
White-pine Shoot Borer, Eucosma gloriola Heinr.
A marked decline in population levels of this shoot borer occurred in Morson
and Kingsford townships in Division 22 and near Williamson Lake north of Atikokan