Annual District Reports: Forest Insect and Disease Survey ... - NFIS

1.1 INTRODUCTION
Excellent growing conditions prevailed throughout most of the
Manitoba-Saskatchewan Region in 1963. Cool weather during May delayed
foliage development from a week to ten days in most areas, but was
followed by near-normal temperatures and abundant rainfall during June
and July. The season ended with light precipitation and much aboveaverage
temperatures setting record frost-free periods in many localities
and allowing the foliage to persist on deciduous tree species late into
the fall.
There were some notable changes in the status of several major
as well as minor insect and disease problems throughout the shelterbelt
and forested sections. The larch sawfly was again the most widely
distributed forest insect recorded at infestation levels, and marked
population increases occurred in several areas, particularly throughout
Riding Mountain National Park and in the extreme northwestern part of
Manitoba. Infestations of the spruce budworm continued to decline in
the Cypress Hills Provincial Forest, Riding Mountain National Park
and on the north shore of Lake Winnipegosis, and remained essentially
the same in the vicinity of Namew Lake on the Manitoba-Saskatchewan
border and along the Churchill and Birch rivers. However, defoliation
in these latter areas was less noticeable and uniform than in past
years due to the excellent foliage and shoot growth on both white spruce
and balsam fir. The balsam-fir sawfly was limited primarily to sprucebalsam
fir stands in the forested areas where there were some notable
changes in distribution and intensity. In general, populations declined
in the northern parts of both provinces, and increased in southeastern
Manitoba and in the Prince Albert and Meadow Lake districts of Saskatchewan.
No change was recorded in the status of the jack-pine budworm in
Saskatchewan, but larval populations were significantly higher in
southern Manitoba, particularly in areas where jack pine produced a
heavy pollen crop, and new infestations occurred in two locales of the
Sandilands Forest Reserve. The localized infestation of pine tube moth
west of Prince Albert, Saskatchewan persisted for the third consecutive
year and damage ranged from moderate to severe. Larvae of the black
headed budworm were more common on spruce and balsam fir throughout
both provinces, and a general increase in populations of the yellowheaded
spruce sawfly resulted in moderate to severe defoliation of
white spruce shelterbelts and woodlots in eastern Saskatchewan for the
first time in several years. Relatively high populations of both the
pine needle scale and spruce spider mite persisted on planted spruce
in several localities. The forest tent caterpillar continued to
defoliate trembling aspen and other deciduous hosts over extensive
areas but there were marked changes in the infestation pattern;
increased distribution in Saskatchewan was off-set by declines in
central and eastern Manitoba resulting in a slight reduction in total
area affected. The outbreak of the aspen leaf beetle, which was