Forest Insect and Disease Survey; Ontario, 1965 - NFIS

D 31
Western Tent Caterpillar, Malacosoma pluviale (Dyar)
Quantitative samples in the district revealed a decline in population levels
of about 40 per cent. Pin cherry was the preferred host but some white birch and
willow were infested (see photograph). Fluctuations in numbers of this caterpillar
are shown in Table 8.
TABLE 8
Summary of Western Tent Caterpillar Larval Colony Counts per Measured Mile
in the Chapleau District from 1963 to 1965
Location
township.
Number of tents per mile of roadside
196 196 196
Manning 13 9 5
*L 12 8 2
Panet 6 6 5
8D 7 21 4
Chewett 34 12 5
Blarney 16 0 5
Floranna 32 26
*Site disturbed by roadbuilding operations in late 1964.
Red—pine Sawfly, Neodiprion nanulus nanulus (Schedl.)
Little change in numbers of this insect has occurred in recent years (Table 9).
Larvae were collected commonly in the central part of the district, particularly
along the Chapleau River within 15 miles of Highway 101 (see map). The medium
infestation that occurred on red pine around Biscotasing Lake in 1964 subsided in
1965.
The insect was found almost exclusively on jack pine, the most abundant pine
species in the Chapleau District. However, single colonies occurred on fringe red
pine trees in Arden and D townships. Defoliation was light throughout the district.
TABLE 9
Summary of Red—pine Sawfly Larval Colony Counts
in the Chapleau District from 1963 to 1965
Location
(township)
Host
Av. d.b.h.
in inches
Av. no, of colonies per tree
1963 1964 1962
Panet jP 8 0.2 0.1 2.1
Chapleau jP 2 0.3 0.1 1. 5
McPhail rP 2 1.4
Gallagher jP 8 0 0 0 .6