Forest Insect and Disease Survey; Ontario, 1965 - NFIS

D
TABU. 9
Summary of Red-headed Pine Sawfly Colony Counts on Red Pine
in Sudbury District in 1964 and 1965
No. of trees
Av. height
of trees in
No. of trees
infested
Av, no. of colonies
per infested tree
Location examined feet in 1 6 196 16. 1964 1965
Cockburn Island 100 4 50 50 2 3
Hallam Township 10 8 8 10 5 8
Spanish River Reserve 50 4 25 37 2 2.7
Salter Township 100 3 3 0 1 0
Red Pine Sawfly, Neodiprion nanulus nanulus Schedl.
A further increase in abundance of this insect occurred in most of the district
in 1965. Light infestations persisted in jack pine stands on Cloche Island, in
Nairn, Rathbun, and Hanmer townships and in parts of a red pine plantation at Nairn.
Light-to-moderate defoliation of scattered red pine trees was observed at several
points in the northwestern part of the district and northeast of Wanapitei Lake in
Norman and Parkin townships. Elsewhere in the district pockets of light defoliation
occurred more frequently than in 1964 (see map).
The most noteworthy increase in numbers occurred on Cloche Island where 90 per
cent of the larval colonies examined were N. nanulus nanulus Schedl, compared with
about 50 per cent in 1964 (see account on N. pratti banksianae Roh.)
Black-headed Jack-pine Sawfly, Neodiprion pratti banksianae Roh.
This sawfly occurred on jack pine in many parts of the district as shown on the
accompanying map. Pockets of moderate to severe defoliation of exposed trees persisted
along lakeshores and roads in the K.V.P. West Branch Spanish River Limits
and in the Onaping and Wanapitei lake areas. However, defoliation inside stands
was negligible. Elsewhere in the district pockets of light infestation or scattered
larval colonies occurred commonly.
As in recent years, two other sawfly species, N. nanulus nanulus and N. pratti
paradoxicus were generally found in association with N. pratti banksianae. A
summary of larval colony counts shown in Table 10 includes all three species.
TABLE 10
Colony Counts of Jack Pine Sawflies on Ten Jack Pine Trees
at Each of Five Locations in Sudbury District
From 1962 to 1965
Location
Av, d.b.h. of trees Ày0 no, of colonies per tree
in inches in 1965 1962 1963 1964 1965
Hanmer Township 4 15 25 3.0 2.4
Nairn " 8 5.5 5.2 6.0 6.0
Rathbun 4 2.4 1.0 0.3 0.8
Cloche Island 4 2.2 1.7 2.0 1.5
Shakwa Lake 6 5.5 6.0 3.5 3.8