SURVEYS 



Each year, this Department participates in the Ontario portion of the Canada- 

 wide Forest Insect and Disease Survey of the federal Department of Forestry. 

 Detailed information concerning the occurrence and distribution of specific insects 

 and disease is contained in the Annual Report of the Forest Insect and Disease 

 Survey. Attention is drawn here to a few well-known pests of special interest. 



As reported last year, spruce budworm activity in northern Ontario has finally 

 subsided after about 45 years of more or less uninterrupted recorded epidemics. 

 Although the budworm did not occur in epidemic numbers in any locality in the 

 north, it was possible nevertheless to find small numbers of the insect over many 

 areas. The heavy infestation on white spruce in the Uxbridge Forest persisted 

 in 1965. 



The current epidemic of the forest tent caterpillar extended in area in 1965. 

 In northwestern Ontario the infestation increased in area to about 35,000 square 

 miles, which includes all of the Kenora and Fort Frances Districts, the southern 

 half of the Sioux Lookout District, and the central third of the Port Arthur District. 

 In the western portion of this area, where the caterpillar has been active for five 

 years, there is evidence that the epidemic is about to die out. Throughout central 

 and southern Ontario there are several areas under attack by the tent caterpillar, 

 totalling about 3,000 square miles. The principal locations are in the western part 

 of the Kapuskasing Forest District, from Sault Ste. Marie to North Bay, the 

 Muskoka Lakes area, south-east part of the Pembroke Forest District and at 

 several points in the Kemptville Forest District. Although this insect occurs in 

 spectacular numbers, and attracts much attention when it strips the leaves from 

 aspen stands in the north and a few additional broad-leaved species in the south, 

 it is ;not an important economic forest insect since it seldom causes permanent 

 damage to trees. 



Larch sawfly populations, which have remained low across Northern Ontario 

 for several years, showed notable increases in the Western Region. This may be 

 the first indication of a return to Northern Ontario of large numbers of this pest. 

 In Southern Ontario this insect continues to be a chronic problem in many stands 

 of tamarack and plantations of European larch. 



The European pine sawfly, an insect native to Europe which entered Ontario 

 via Windsor about 1940, continued to spread and increase in severity. The insect 

 feeds principally on Scots, red and jack pines. 



During 1965, the eastern boundary of its occurrence extended eastward a 

 few miles, and is now a line roughly from Midland to Barrie, around the south 

 shore of Lake Simcoe, and south-easterly through Lake Scugog to Colborne on 

 Lake Ontario. An isolated outbreak persisted at Belleville, but of special 

 significance was the discovery of the insect in Scots pine plantations at two locations 

 on Manitoulin Island. This means that the sawfly is now close to the jack pine 

 stands of Northern Ontario. Plans are being made to control the insect on the 

 Island. 



During the past five years, attention has been drawn to the rather spectacular 

 late summer browning of birch trees caused by the birch skeletonizer. Outbreaks 

 of this insect, in addition to having almost no injurious effects on the trees, have 

 now largely died out. 



The most noticeable tree disease in Ontario is the Dutch elm disease. The 



112 



