here. - Ministry of Forests, Lands and Natural Resource Operations

In the Thompson-Okanagan Region, western hemlock looper was found at 69% of the 16 three-tree beating sites
sampled, with an average of 9.6 larvae per site, down from 28.0 larvae per site in 2011. Decline of the hemlock
looper in the Serpentine and Mud Lake sites was likely due to the operational spray program undertaken in 2012.
In the North Thompson, few larvae were recorded at Finn Creek and TumTum Lake and no larvae were found at
Serpentine Creek, Thunder River, Mud Lake and Murtle Lake (Table 14). Population trends in the Mabel Lake/
Three-Valley Gap to Scotch Creek area varied, with small increases at Perry River North and Yard Creek, and
significant decreases at Three Valley Gap, Perry River South and the Mabel Lake area (Kingfisher Creek and
Noisy Creek). Minor decreases in larval abundance were noted at Scotch Creek and Crazy Creek. Larval populations
increased slightly, just south of Sugar Lake along the Shuswap River and Greenbush Lake. Figure 8 shows
the variation from 2010 to 2012 in the number of western hemlock looper larvae present in three-tree beatings at
sites in the Thompson Okanagan Region.
In the Kootenay-Boundary Region, western hemlock looper was recorded at 63% of the 25 three-tree beating
sites sampled, compared to 84% in 2011, and 71% in 2010 (one site was not sampled in 2012 due to flooding).
Larval counts were down slightly with an average of 18.9 per site in 2012 compared to 21.9 per site in 2011. The
highest larval counts were east of Revelstoke at Beaver River and Jumping Creek, followed by two sites north
of Revelstoke at Bigmouth and Pitt Creeks. The only sites with notable larval increases were Sutherland Falls,
Martha Creek and Jumping Creek. Overall populations south of Revelstoke decreased from an average of 5.6
larvae per site to 1.8 larvae per site, while north and east of Revelstoke, the average larval count decreased from
39.5 larvae per site to 21.0 larvae per site (Figure 9). These decreases are in part due to the 2012 operational spray
program conducted north of Revelstoke at the Goldstream and Downie Creek sites. Trace defoliation was noted
at two sites: Goldstream River and Pitt Creek.
The three major defoliators found during the 2001 to 2003 outbreak in the Kootenay Boundary Region were
western hemlock looper, sawflies and western blackheaded budworm, in order of relative abundance. Since 2008,
sawflies numbers have remained consistent, while hemlock looper numbers increased in 2011 and 2012. Very
low numbers of western blackheaded budworm have been observed since 2006.
Figure 8. Western hemlock looper larval counts at sixteen sites in the Thompson Okanagan Region
from 2010 through 2012.
Ministry of Forests, Lands and Natural Resource Operations, Kamloops, B.C.
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