Forest Insect and Disease Survey; Ontario, 1965 - NFIS

B 20
TABLE 14
Summary of Introduced Pine Sawfly larval Counts
in Lake Simcoe District in 1964 and 1965
township Location
Tree
species
Av. d.b.h.
in inche
Total number of larvae
er 15-tray sample
1965
1
Pickering scP 6 13 67
Reach scP 6 111 41
Melancthon scP 4 6 0
Mono scP 7 199 3
Vespra scP 5 0 2
Oro wP 4 17 8
Jack-pine Needle Miner, Exoteleia pinifoliella (Cham.)
Heavy infestations of this needle miner have persisted for several years in
jack pine plantations in Flos, Vespra, Whitchurch, Uxbridge, and Albion townships.
In Albion Township surveys showed 45.6 per cent of the current year's needles were
killed by primary mining of the insect and most of the old foliage was mined. Light
infestations were common elsewhere in the district.
Sugar-maple Borer, Glycobius speciosus (Say)
Recurrent attack by this large beetle in recent years caused severe damage to
mature sugar maple trees in a 5-acre stand near Newmarket in East Gwillimbury Township
(see photographs).
The eggs are laid under bark scales or in crevices pf the bark from which the
larvae mine directly between the bark and wood s usually across the grain of the wood.
Larval mines causing large open wounds girdled and killed some trees, other mines
healed but were easily detected by ridges and gall-like swellings in the bark.
high proportion of branches were girdled and killed. In addition, the value of
the trees was greatly reduced by the damage and, the accompanying wood stains.
Birch Leaf Miner, Fenusa pusilla (Lep.)
Marked increases in the extent and intensity of infestations of this sawfly
occurred in 1965 (see map). Heavy infestations were observed commonly on weeping
birch ornamentals in the district. At many locations 90 per cent of the leaves
were mined and 75 per cent of the leaf surface damaged. Infestations were generally
light in white birch stands.
Pales Weevil, Hylobius pales (Hbst.) and the Northern Pine Weevil,
Pissodes approximatus Hopk.
These weevils continued to be major pests in Scots pine plantations where
Christmas trees were harvested three or more consecutive years and in plantations
where considerable tree mortality resulted from heavy infestations of the root
collar weevil, Hylobius radicis Buch. The extent of dame to the branches of
living trees by adult weevil feeding was proportionate to the numbers of stumps