ORNAMENTAL AND SHADE TREES 



163 



latitude, species, etc., but in general an annual spraying 

 with a fungicide at the beginning of the growing season 

 will be effective. 



The stem and branch fungi with inconspicuous or 

 hidden fruiting bodies form a small class, but contain 

 several very serious tree diseases. Those of interest to 

 the arborist are: 



FUNGUS DISEASE LEADING TO A HOLLOW TRUNK IN A 

 VALUABLE OAK TREE 



1. Chestnut blight, which is the most serious of all 

 our tree diseases. It is well understood and does not 

 warrant any elaboration at this time. It is perhaps suffi- 

 cient to say that its remedy has not been discovered, and 

 that it bids fair to exterminate our only native chestnut. 



2. The hardwood canker is a stem disease of hard- 

 woods closely resembling the chestnut blight in appear- 

 ance and methods of attack. It is particularly common 

 on the horse chestnut. The trouble may be partly con- 

 trolled by pruning away the infected portions and pre- 

 vention of wounds, since the disease enters through 

 them. 



3. Black knot, a familiar disease, attacks practically 

 all the cherries and is particularly common on wild and 

 red cherry. The fungus causes black knotty growths 

 over the crown, usually the smaller branches, often kill- 

 ing the tree. A careful pruning away of the infected 

 portions early in the spring, and again late in the sea- 

 son, should control the trouble. An application of Bor- 

 deaux mixture in the late winter and one in the spring 

 when the buds begin to open should be a further guar- 

 antee of success. 



The stem and branch fungi with large and conspicuous 

 fruiting bodies (the wood-rotting fungi) form a large 

 class, and they produce the decay which in most in- 

 stances necessitates tree repair. While the fruiting bod- 

 ies of this disease are a key to this class it should be 

 remembered that the disease may be present for a num- 

 ber of years without forming fruiting bodies. The 

 diseases are included in four large families, and there 

 are about twenty-five important species. Of this number 

 the most important ones attacking deciduous trees are: 



1. Dadalea, with three species, common on oaks. 



2. Polyporus, with six species. The striking "sulphur- 

 like" fungus is perhaps the most interesting and danger- 

 ous of the group. It is found on oak, ash, locust, and 



butternut. Another important one of the group is a 

 white hooflike fungus which is quite common on gray 

 birch. White rot of red cedar is another dangerous 

 disease. 



3. Fomes, with nine important species, found on a 

 large number of deciduous trees and a few evergreens. 

 Members of this group attack beech, maple, yellow birch, 

 sycamore, ash, and black locust. Of the evergreens, pine, 

 spruce, and fir are attacked by tinder fungus or rot of 

 conifers. 



When one becomes interested in the diseases of this 

 class they have usually developed to such an extent that 

 the only practical solution lies in tree repair. Chisel and 

 gouge must then be used to remove all diseased material, 

 and a water-proof concrete filling put into the cavity. 

 Other suggestions of value would include the following: 



1. Destroy all fruiting bodies and infected parts. 



2. Avoid the making of wounds, and properly treat all 

 wounds that are made in pruning. 



3. Practice clean culture generally, aiming to keep all 

 trees in the most vigorous condition. 



DISEASES OF THE ROOTS 



From our point of view, only two important diseases 

 are included in this group. They are: 



1. Root rot, attacking the roots of a large number 

 of conifers, including red and white spruce, balsam fir, 

 arbor vitae, Scotch pine, and larch. 



2. The honey agaric, attacking the roots of a large 

 number of coniferous and broad-leaved trees. 



No valuable means of controlling these root diseases 

 has been suggested. 



In concluding it is probably safe to say that fungus 

 diseases will give the arborist little concern where the 

 trees are kept in a vigorous condition, and where clean 

 culture is practiced. Tree diseases resulting from the 

 attacks of fungi are usually secondary, following insect 

 damage, starvation, breakage, abrasion, or some simi- 

 lar cause. 



QUESTIONS AND ANSWERS 

 Q. Please advise me in regard to shag bark hickories, 

 whether they can be successfully grafted, and if so 

 whether grafts from trees bearing high grade thin 

 shelled hickory nuts can be obtained and at what season 

 of the year the graft should be set. Also please give 

 instructions for the proper setting of the graft. Also 

 please advise me in regard to the setting of white pines, 

 at what season of the year they should be set out, where 

 they can be obtained and any instructions for setting the 

 trees, etc. E. P. McK., Binghamton, N. Y. 



A. I cannot give you much information on the first part 

 of your question, but would suggest your writing the 

 P. J. Berkmans Company, Augusta, Georgia, who 

 specialize in grafting pecans. Dr. W. C. Deming, of 

 Georgetown, Connecticut, who is secretary of the North- 

 ern Nut Growers Association, will also be able to put 

 you in touch with some one who can answer your ques- 

 tion fully. 



To your second question, white pines can be set out 



