Canadian Forest Service Publications
Infestation ratings of the larch sawfly in Manitoba and Saskatchewan. 1960. Nairn, L.D.; Prentice, R.M. Forestry Chronicle 36(3): 225-229.
Issued by: Northern Forestry Centre
Catalog ID: 30743
Larch sawfly infestations are commonly surveyed from the ground and air. Ground surveys are based on estimates of defoliation and proportion of tamarack shoots utilized for oviposition. Aerial surveys are based on colour ratings discernible at an altitude of 600 feet. The proportional distribution of shoots and foliage of tamarack was studied and found to be similar for four different crown types. The paper attempts to rate infestations so that either ground or aerial surveys will give comparable results.