high losses by feeding on the bark of seedlings during the winter. Approximately 

 650 acres were treated with zinc phosphide in area to almost 29,000 square miles 

 in 1964, which includes all of the Kenora District, the northern one-half of the 

 Fort Frances District, the southern part of the Sioux Lookout District, and the 

 western fringe of the Port Arthur District. This insect feeds mainly on poplar in 

 the north, and on several species of hardwoods in the south. There are several 

 scattered areas infested by the caterpillar throughout central and eastern Ontario, 

 totalling about 1,200 square miles. Chief among these are areas near Sault Ste. 

 Marie, west and southwest of Lake Nipissing, the Muskoka Lakes, and the eastern 

 portion of the Pembroke District. 



Larch sawfly populations across northern Ontario remained very low again in 

 1964. However, in southern Ontario damage by this insect was medium to heavy 

 in several stands of tamarack and plantations of European larch. 



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

 via Windsor about 1940, continues to spread eastward in southern Ontario. Al- 

 though the eastern boundary of where the insect occurs did not advance materially 

 in 1964, and remains roughly from Midland — Barrie — Port Perry and southeast to 

 Lake Ontario just east of Newcastle, there was a marked increase in damage 

 throughout southwestern Ontario. This sawfly feeds principally on Scots and red 

 pines. 



The birch skeletonizer causes late-summer browning of white birch leaves 

 which, while spectacular in appearance, does not affect the trees adversely. The 

 infestation of this insect in southern and central Ontario virtually disappeared in 

 1964, but the shift to the north continued, resulting in a wide swath of severe 

 browning of birch from Larder and Abitibi Lakes westward for control of mice. 



The major tree-killing disease in the forests of Ontario is the blister rust of 

 white pine. A substantial control programme, which is tied in to the broader inten- 

 sive management of white pine, has been in progress for several years. The disease 

 is controlled by using the herbicide 2, 4, 5-T to kill the obligate alternate host 

 plants, wild currants and gooseberries, in the immediate vicinity of the pines. In 

 1964, 7,500 acres of high-value young white pine stands were protected against 

 the blister rust in parts of the Sault Ste. Marie, North Bay, Pembroke, Tweed, 

 Kemptville and Lake Huron Districts. 



The fomes root rot, a killing disease with a potential for causing high losses 

 in both young and older trees, is causing concern in several areas of the continent. 

 The principal outbreak centres in Ontario are in red-pine plantations at St. Wil- 

 liams in the Lake Erie District, and at the Orr Lake Forest in the Lake Simcoe 

 District. A recommended method of control is to apply sodium nitrate to all freshly 

 cut stumps as soon as trees are cut in plantations. This procedure was conducted 

 in 1964 for the second consecutive year and covered 600 acres of thinning oper- 

 ations. 



Radio Communications 



A small increase in the number of radiograms transmitted over the Radio 

 system was recorded for 1964. A total of 91,803 messages were sent with a word 

 count of 2,645,931. Additionally, much spontaneous unrecorded communications 

 to and from aircraft, vehicles and portable units took place. 



Three more VHF radiotelephone stations were added to the System, being 

 located at Remi Lake Park, Bass Lake Park and Point Farms Park. 



Thirty-three Automatic Direction Finder installations were purchased and 



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