1921-22 DEPARTMENT OF LANDS AND FORESTS 253 



avoid and eliminate this type. From our own analyses of butt-rotted balsams 

 made in 1922 in the Temagami Forest Reserve we have found that balsams under 

 sixty years of age are as a rule free from attack. But for all types many more 

 analyses should be made before final conclusions can be reached. 



Spruce Bud Worm. — At the request of the Federal Entomological Branch 

 in 1921, an examination of dying balsam, primarily injured by the spruce bud 

 worm, was made to determine to what extend fungi were responsible for the de- 

 cadence of these trees. The first studies were made at Otter. It was soon dis- 

 covered that the absorbing roots of such trees were dead, and that in consequence 

 the trees were dying from inability to obtain water and nourishment from the 

 soil. An explanation of the death of the roots seems apparent; injury to the 

 foliage by the bud worm meant loss of the power to manufacture food, and the 

 roots, dependent on such food, are starved and die. Thus a vicious circle is 

 established. Mr. Hiley has also pointed out that the flow of materials in bud 

 worm injured trees would be greatly lessened, because of the abrupt decrease in 

 the size of the annual rings. That such a condition would afifect the health of 

 the tree is quite obvious. They, too, would in all probability the more quickly 

 succumb to the attacks of butt and heart rot fungi. But as many of the dying 

 or dead trees are free from butt and heart rot fungi, it is clear that the physio- 

 logical disturbances are quite sufficient to cause their death. In the case of 

 surviving bud worm injured trees it would be interesting to compare the ravages 

 of the butt and heart rot fungi in them with what takes place in uninjured trees 

 of the same class. Do such trees, for example, suffer more severely from the 

 "hemlock rot", and if so, to what extent? Casual observations indicate that 

 they do, but there are no data on this subject. 



Indeed, from the standpoint of utilization, data should be collected relative 

 to the subsequent history of balsam stands attacked by the spruce bud worm. 

 Some trees die during the bud worm epidemic, but a large proportion survive. 

 Then a few years after the epidemic has passed, as clearly stated by Mr. Hiley, 

 "great numbers of the convalescent trees mysteriously died; and as this mortality 

 continued for several years the loss appears in some places to have been as great 

 as that which resulted from bud worm feeding." 



3. Balsam Rusts. 



The foliage of balsam (Abies halsamea) is subject to the parasitism of 

 many rust fungi. In all cases these rusts parasitize an alternate host, so that 

 there are two phases in their life cycles. Thus one alternates between the blue- 

 berry and the balsam, another between the fireweed and the balsam, a third 

 (comprising several species) between various ferns and the balsam, a fourth 

 between chickweeds and the balsam, and a fifth between willows and the balsam. 

 The fern rusts of the balsam cause the greatest damage, especially to seedlings 

 and younger trees. The others are probably of little or no economic importance 

 at any time. The chickweed rusts of the balsam are the cause of the often large 

 conspicuous crows' nests or witches' brooms common enough on the balsam in 

 some localities. 



The willow rust of the balsam appears as small open pustules on the affected 

 needles. All of the others form small white or yellow cylindrical bladders on 

 the discoloured (usually whitened) affected needles. These bladders, or peri- 

 dermia, as they are called, break irregularly at their apices to discharge their 

 spores; the latter are capable of infecting the alternate host only. 



Two new species were described and named by Dr. H. P. Bell, in 1922, 

 from abundant material discovered in the Temagami Forest Reserve. Both 



