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

There is an ongoing study to calibrate two egg collection methods for western hemlock looper in the Cariboo.
These two methods are: standard arboreal lichen collection, and a less time-consuming method using foam strips
stapled to the boles of trees. The data have not yet been completely analyzed, however there does not seem to
be any direct correlation between moth trap catches and either method for egg counts (Tables 16, 17). A similar
study in the Kootenay Boundary Region being conducted by Dr. Art Stock will help clarify this relationship.
Based on current western hemlock looper population data, no population control will be necessary in 2013. To
further monitor and assess population levels, lichen samples should be collected in spring of 2013 in western
hemlock looper hotspots such as Tasse Lake to assess the level of egg parasitism. Pheromone trap clusters for
adults and foam strips for eggs should be deployed in mid-summer in those same areas. Methodology for foam
strip deployment involves the use a white polyurethane (10 mm thick) foam strip (17 cm × 30 cm) placed above
breast height (as high as possible) on the bole of a western hemlock tree, stapling only the top portion of the foam.
The foam is curved slightly outward at the top, so moths are able to access the lower side of the foam to lay eggs.
Foam strips should be placed at least 10 metres from opening edges to reduce the impact of exposure to wind,
rain, and road dust. Lichen samples should be collected at western hemlock looper foam egg monitoring sites to
aid with the calibration of the foam egg data. Based on 2012 moth catches, additional three-tree beating sampling
should be performed in areas with high moth numbers, as well as at regular sampling locations.
Number of
Average Number Healthy Eggs Number
Location of Moths per Trap Foam Lichen1 Table 16. Results of three-tree beatings, western hemlock looper moth trap catches, and egg monitoring
in 2012. Eggs were counted from foam strips and lichen placed at two trapping sites.
of larvae
Archie/Bouldery Creek (6108 km) 141 11 n/a n/a
Archie/Bouldery Creek (6110 km) 333 38 n/a n/a
Archie/Bouldery Creek (6113 km) 190 37 n/a n/a
Archie/Bouldery Creek (6114.5 km) 139 5 n/a n/a
Abbott Creek 27 1,072 7 n/a n/a
Abbott Creek 28 700 n/a n/a n/a
Cariboo Lake 8411 km 367 0 n/a n/a
Hen Ingram Lake 144 7 7 43
Tasse Lake 3T96 1,913 200 44 127
1 number of healthy eggs per 100 grams of dry lichen
2 number per three-tree beating
# Eggs per Foam Strip1 Table 17. Comparison of healthy, infertile and parasitized western hemlock looper eggs collected on foam
strips and lichen at Hen Ingram Lake and Tasse Lake, 2012.
# Eggs/100 g Dry Lichen
Site Healthy Infertile Parasitized Healthy Infertile Parasitized Parasitized Old
(new) (new) (old)
Hen Ingram Lake 7 0 10 7 3 2 44 17
Tasse Lake 200 10 41 44 5 21 11 27
1 number of eggs per 17X30 cm foam strip. There were no old eggs or old parasitized eggs on the foams because they were placed after looper
egg oviposition for 2011.
Ministry of Forests, Lands and Natural Resource Operations, Kamloops, B.C.
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