FOREST PEST CONTROL 



In 1970, the spruce budworm continued to dominate the 

 insect and disease problems, not only in Ontario but 

 throughout eastern Canada. In Ontario, infestations of the 

 insect were prevalent in three broad areas — west of the 

 lakehead, the northeast, and in the southeast. 



In northwestern Ontario, as a result of the spraying 

 projects in 1968 and 1969 in the Burchell-Shebandowan 

 Lakes area, the budworm situation was relatively satisfactory 

 in 1970. The new area of infestation around Northern Light 

 Lake, mentioned in last year's report, was sprayed (see 

 section on control), but preliminary results indicate a sur- 

 viving population for 1971. In addition, a new area of in- 

 festation, causing considerable concern, was discovered late 

 in the season along the international border in the southern 

 part of the Fort Frances district. The full extent of this infes- 

 tation could not be determined before the end of the field 

 season. 



Many of the separate infestations in northeastern Ontario 

 coalesced into three principal areas. The infestation, centred 

 on the northern part of the Chapleau district, enlarged to 

 6,500 square miles and extended as far west as Lake Superior 

 Provincial Park; the Onaping infestation in the Sudbury dis- 

 trict increased to 1,200 square miles; and the scattered in- 

 festations in the Swastika district increased to 450 square 

 miles. 



In southeastern Ontario, the total area of infestation in- 

 creased from 1,200 square miles in 1969 to 2,500 square 

 miles in 1970. The principal areas involved were the Ottawa 

 Valley from about Stonecliffe to Ottawa, including eastern 

 and south-central portions of Algonquin Provincial Park; east 

 of Bancroft in the Tweed district; and in the northern part 

 of the Lindsay district. 



The jack-pine budworm, which had subsided in north- 

 western Ontario in 1969, declined sharply in numbers in the 

 Pembroke district in 1970. This sudden development lead 

 to cancellation of a planned spraying project near Lake 

 Traverse. However, high populations of the insect continued 

 to damage jack-pine stands particularly in the vincinity of 

 the French River from Lake Nipissing to Georgian Bay, and 

 south along Georgian Bay into Harrison Township. High 

 populations also occurred south of lllfed Lake in the Parry 

 Sound district. 



The only notable area of forest tent caterpillar activity 

 was in the Fort Frances district where the insect continued 

 to defoliate stands of poplar, west and north of the Town 

 of Fort Frances, over an area of about 500 square miles. 



The European pine sawfly did not add significantly to the 

 main body of its range in southern Ontario, the eastern 

 boundary being a line roughly from Midland to Kingston. 

 The insect occurs also on Manitoulin Island, and on 

 ornamental plantings in the cities of Sault Ste. Marie, North 

 Bay and Ottawa. 



The saddled prominent, an insect which only rarely occurs 

 in outbreak proportions in Ontario, has been defoliating 

 sugar maple woodlots in parts of the Lake Simcoe and Lake 

 Huron districts since 1967. As predicted last year, the infesta- 

 tions showed a distinct decline in 1970, and the large in- 

 festation in the Parry Sound district collapsed. Infestations 

 are expected to largely disappear by 1971. 



Two insects, which infrequently occur in outbreak pro- 

 portions, caused widespread defoliation of hardwoods 

 across northern Ontario. The large aspen tortrix, a close 

 relative of the spruce budworm, defoliated trembling aspen 

 over a total area of about 20,000 square miles, principally 

 throughout areas of northwestern Ontario. The birch skele- 

 tonizer browned white birch trees over a total area of at 

 least 25,000 square miles at several locations from north- 

 western Ontario to the Ottawa Valley. 



As noted in the 1969 report, the geographic range of the 

 Dutch elm disease has largely stabilized, with only a small 

 northern extension in the vicinity of the cities of Sault Ste. 

 Marie and North Bay. Mortality of elms continued at an 

 accelerated rate in the central part of southern Ontario. 



The scleroderris canker of red and jack pines continued 

 to cause some mortality of regeneration of these species in 

 several areas of northern Ontario. The most significant losses 

 are in young plantations. In 1970, the disease was found for 

 the first time in the Thunder Bay nursery. 



There were many additional insect and disease problems, 

 but the foregoing are of greatest significance and interest to 

 forestry. 



CONTROL OPERATIONS 



The total area sprayed in 1970 to control the spruce bud- 

 worm amounted to almost 23,000 acres. In northwestern 

 Ontario, the only area requiring spraying was in the general 

 vicinity of Northern Light Lake — specifically, immediately 

 to the south of the lake, at the east end of Granite Lake, and 

 along the northern edge of Gunflint Lake — 11,000 acres in 

 total. The 5,250 acres at Northern Light Lake and 2,250 acres 

 at Granite Lake received two applications of the insecticide, 

 fenitrothion, each application at 5.1 oz. per acre, and the 

 3,500 acres along Gunflint Lake received one application of 

 5.1 oz. per acre. The spraying was successful in arresting 

 the infestation, but a sufficient number of insects survived 

 to probably constitute a problem in 1971. 



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