boundary, and immediately west of the City of Sudbury. 

 Because of the scattered nature of these developing out- 

 breaks and the relatively low economic importance of the 

 stands containing balsam and white spruce, it was not 

 feasible to aerial-spray with msecticide in an attempt to 

 prevent their development 



In southeastern Ontario, the budworm also caused notice- 

 able defoliation of white spruce and balsam trees through- 

 out many sections of the Ottawa Valley from Mattawa to 

 Ottawa, and into some areas south and southeast of Ottawa. 



The jack-pine budworm, a close relative of the spruce 

 budworm, has occurred in large numbers in many areas of 

 the Province since 1966. in 1968, there was some reduction 

 in activity of this insect in northwestern Ontario, but it still 

 caused severe defoliation of jack-pine stands over about 

 one-half of Kenora Forest District. Some top-killing of trees 

 occurred on poor sites. The insect also caused considerable 

 defoliation throughout parts of central and eastern Ontario, 

 notably at locations in the Forest Districts of Sault Ste. 

 Marie, Sudbury, Parry Sound, North Bay and Pembroke. In 

 High-value stands, such as at the Kirkwood Unit of Sault 

 Ste. Marie where it is defoliating red pine as well, and near 

 Lake Traverse in the Pembroke district, the budworm is 

 being observed carefully for possible need for spraying in 

 1969. Outbreaks of this insect are not usually sustained to 

 the point of causing significant mortality of trees. 



The forest tent caterpillar epidemic, which in 1967 occur- 

 red mainly in poplar stands in the Fort Frances and Sault Ste. 

 Marie districts, declined to a relatively unimportant level 

 in 1968. Populations persisted in an area of about 400 

 square miles surrounding the town of Fort Frances, and in 

 an area of almost 800 square miles along the southern 

 portion of the Sault Ste. Marie district. In 1969, the out- 

 break should decline further. 



In 1968, the European pine sawfly did not add significantly 

 to its range in an easterly direction, and the eastern extrem- 

 ity remained in the area of Belleville and Prince Edward 

 County. Since its introduction to Ontario near Windsor 

 about 1940, it had been spreading eastward at a rate of 15 

 to 20 miles each year. The insect occurs also on Manitoulin 

 Island, and in 1968 was found for the first time on orna- 

 mental plantings in the Cities of North Bay and Sault Ste. 

 Marie. 



The saddled prominent is an insect which defoliates 

 hardwood stands in a spectacular fashion similar to the 

 forest tent caterpillar. Prior to 1967, noticeable outbreaks 

 of this insect in Ontario had been recorded on only two or 

 three occasions. In 1967, woodlots in three townships sur- 

 rounding Orillia were infested, and in three townships near 

 Owen Sound. In 1968, some of these outbreaks expanded 



and new centres developed with the result that severe 

 defoliation occurred in Eastnor, Albemarle and Keppel 

 Townships in the Lake Huron district, and in Oro and 

 Medonte Townships and on Christian and Beckwith Islands 

 m the Lake Simcoe district. The latter district also had lesser 

 infestations in Adjala, Tiny, Whitchurch and Uxbridge 

 Townships. Of particular interest was a new outbreak of 

 about 1,000 square miles in the eastern part of the Parry 

 Sound district, extending into the western portion of Algon- 

 quin Provincial Park. Although the current outbreaks of 

 the saddled prominent are by far the most severe ever re- 

 corded in Ontario, past experience here and in the U.S.A. 

 indicates that it persists for only two or three years in any 

 locality and therefore seldom causes permanent injury to 

 trees. 



The most noticeable tree disease in Ontario is the Dutch 

 elm disease. There was little extension of range during 1968, 

 probably because the disease is as far north as Sudbury and 

 Sault Ste. Marie, and further spread northward into the 

 northern forests, where elm is a minor species, will be 

 much slower. 



The Scleroderris canker, a relatively new problem which 

 often kills red and jack pine seedlings, did not increase in 

 intensity or range during 1968. On the other hand, Fomes 

 annosus root rot, a serious threat to the management of 

 pine plantations, was found for the first time in the impor- 

 tant Larose Forest, Kemptville Forest District. It is now 

 known to occur in parts of the Lake Erie, Lake Simcoe, 

 Lindsay and Kemptville districts. Steps are being taken to 

 limit the spread of outbreak centres and to prevent further 

 infections. 



In 1968, a dying-back of branches was very noticeable 

 in mature and over-mature stands of yellow birch over a 

 total area of about 2,500 square miles in the Sault Ste. Marie 

 district and in Algonquin Park, giving the trees a greyish 

 appearance when viewed from a distance. The most ap- 

 parent explanation is that the extremely heavy seed crop 

 of 1967 resulted in poorly formed buds near the branch 

 tips, and most branch tips died. Most of the trees are 

 expected to recover. 



CONTROL OPERATIONS 



Immediately following World War II, the insecticide DDT 

 became established as the most efficient and versatile in- 

 secticide ever discovered, and consequently revolutionized 

 pest control around the world. However, its durability or 

 persistence lead to controversies in many countries con- 

 cerning the long-term effects on other living things, particu- 

 larly fish and wildlife. Early in 1968, the Department became 

 one of the first government agencies in Canada to discon- 

 tinue completely the use of DDT. 



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