DIVISION OF BOTANY 847 



SESSIONAL PAPER No. 16 



carefully iu the winter and cut out everj^ speck of blighted wood so that the chances 

 of spring infection may be lessened as much as possible. During the summer all 

 blight prunings should be made by a knife dipped after each cut in corrosive sublimate 

 (1-1000) so as to preclude carrying infection from tree to tree. In orchards where 

 blight is bad, as a preventive measure it is generally found that it is better to do 

 as little cultivation as will ensure the proper development of the fruit and to avoid 

 all means which tend to produce soft sappy growth. 



Pf:AR Leaf Spot (Septoria piricola Desm.) occurs all over the peninsula, but 

 ordinarily when the dormant spray of lime-sulphur as described under the apple has 

 been thoroughly applied there is little or no trouble from this cause. 



Scab (Ventura pirina Aderh.) is found to be hard to control on several suscept- 

 ible varieties such as Flemish Beauty, Duchess, Sheldon, Seckel, and Anjou. It has 

 been found, however, that the treatment given for Apple Scab is effective in eon- 

 trolling Pear Scab as well. 



Collar Rot. — As noted under the apple, the pear is often killed by collar rot, 

 especially where the soil is wet, and lacking in humus. 



QUINCE. 



Rust {Gymnosporangium L. globosum Farl.). — Quinces are not grown 

 very extensively in the Niagara peninsula, but among the numerous small 

 orchards found throughout the district the chief disease which affects 

 this fruit is the .Rust. The prevalence of this disease is directly attri- 

 butable to the occurrence everywhere of. the red cedar on which a part 

 O'f the life cycle of the Rust is passed. The most obvious method of con- 

 trol would be to destroy all the cedar trees within the possible limits of infection. 

 It has been stated on good authority that the spores may travel a mile or more, so that 

 the destruction of this soui-ce of infection could only be carried out by concerted 

 action of neighbouring owners or else by municipal regulation. It is doubtful if under 

 existing circumstances this method of dealing with the disease would be feasible. 

 It has been claimed that Bordeaux mixture applied at the infection period which is 

 abtput the last of April or the first of May will give satisfactory control of the disease. 



Black Rot of Fruit and Leaf Spot (F/xhrwa maculata Atk.) (=Entomosporium 

 maculatum Rev.).— These are due to the same fungus. Neither is at all prevalent 

 where the dormant spray of lime-sulphur is used. 



V 



cherry. 



Black Knot (Plowiiglitia morhosa Sacc). — A good deal of Black Knot still exists 

 throughout the peninsula, principally in small gardens, waste places, and neglected 

 farms. In the large commercial orchards it is practically non-existent, and no trouble 

 is experienced in keeping them free from it by the simple expedient of cutting .out 

 all knots as soon as they appear. The winter pruning is usually sufficient, but as 

 spores are formed twice in the season, once in early spring and again in late fall, 

 greater security from infection is obtained by an additional summer inspection and 

 removal of the knots. 



Brown Rot (Sclerotinia fructigena Schr.). — Little attempt has been made to 

 .keep this disease in check, and yearly there is a considerable loss from it, mainly 

 among sweet cherries. In 1913 a few days of moist warm weather just at the end of 

 the sweet cherry season resulted in a large amount of rot. 



Shot Hole (Cylindrosporium padi Karst). — This leaf affection is more or less 

 universal on the cherry, and while it is usually not sufficiently severe to warrant the 

 ] ('•> — 55i Ottawa 



