a1 Forest Insect Laboratory, Sault Ste. Marie, Ontario
The aspen blotch miner, Lithocolletis salicifoliella, Cham., has been abundant on trembling aspen, Populus tremuloides Michx., throughout central Canada for the past few years. The mines of this species are found on the underside of the leaves, and are often abundant enough to cause premature browning of the foliage. This insect first came to the attention of the Forest Insect Survey of Ontario in the vicinity of Lake Nipigon in 1944. By 1950, the infestation covered all but the southern part of Ontario, and was reported in most aspen stands in Manitoba and Saskatchewan. The intensity of the infestation in the northern part of Ontario began to decline by 1952, and in 1954 damage was negligible.
(Received March 27 1956)
1 Contribution No. 272, Forest Biology Division, Science Service, Department of Agriculture, Ottawa, Canada.