Surveillance of the large forested areas of British Columbia by personnel of the Forest Insect and Disease Survey, Canadian Forestry Service, involves ground examinations, supplemented by limited observations from small aircraft. The increasing demand for better information, however, has resulted in a search for improved methods. One answer seems to be aerial photography, which offers a permanent accurate record. Conventional aerial photographs are useful but are expensive to obtain and interpret. This study has determined that the boundaries and intensity of a variety of forest pest infestations can also be delineated on color photographs at some of the smallest scales (about 1:137,000) available, and at least some infestations that contrast well with surrounding forests can also be seen on ERTS-1 imagery. The latter has the advantage of being routinely available and cost shared by various users, while normal photography requires a specific mission. Results with ERTS-1 are encouraging, and likely improvements in future resource satellites may be of increasing value in survey programs.