REPORT OF THE HORTICULTURIST 125 



SESSIONAL PAPER No. 16 



Rot, it affects leaves, stems, and fruit. The disease causes slightly depressed patches 

 on the shoots, somewhat like Authracnose, but are not so deep. The stems, however, are 

 not usually badly affected, but it is the leaves and fruit which suffer most. Unlike the 

 Black Eot, in which the mj'celium does not extend far into the tissue of the plant, in 

 the case of Brown Kot once an infection takes place the disease spreads through the 

 tissues of the vine; and when the leaves are affected they turn pale where the disease 

 has been at work, and about this time the under part of the affected part of the leaf 

 becomes downy, indicating the presence of spores and presenting the ' Downy Mildew ' 

 stage of the disease. After this the affected parts of the leaves turn brown. As pre- 

 viously stated, the diseased condition of the fruit is indicated by a brown patch which 

 spreads over the whole grape, which gradually withers. The absence of black pustules 

 readily distinguish this at this stage from the Black Kot. Sometimes after the fruit 

 iias withered it becomes covered with a white powdery substance, indicating the spores, 

 but these do not always develop. Treatment. — Spray with Bordeaux mixture juit before 

 blossoming, after fruit has set, and ten to fourteen days later. 



Powdery Mildew (JJncinula spiralis). — This disease does not penetrate into the 

 tissue of the plant as the Black and Brown Rot, but grows upon the surface, making 

 it much easier as the Black and Brown Rot, also, it spreads more rapidly in 

 rather dry weather. The mildew grows on the young shoots and upper surface 

 of the leaves and on the fruit, giving them a grayish, powdery appear- 

 ance easily recognized as being caused by the Powdery Mildew, This 

 disease feeds on the plant by sending small suckers into the plant cells 

 from which it gets food. Spores are produced early in tlie season and 

 these being scattered about soon infect other leaves or vines and spread the disease. 

 A second crop of spores is produced later in the summer and these carry the disease 

 over the winter. These are enclosed in a hard, roundish case which becomes black 

 during the latter part of the season. Treatment, — This is a very easy disease to treat 

 and yields readily to fungicides. Dry sulphur and sulphur and water have been found 

 effective, but as this disease often accompanies other diseases of the grape, the spray- 

 ings with Bordeaux mixture recommended for Black and Brown Rot are preferable 

 and will effectually check it. 



Ripe Rot, — A species of ripe rot has affected a few varieties at the Central Experi- 

 mental Farm, Salem and Peabody being two of the most affected. The fruit is quite 

 plump and juicy up to the last, but about the time of ripening, the fruit turns brownish 

 an the affected part and often bursts, 



Grai)e Leaf Blight (Cladosporium viticolum). — A disease noticed in the vineyardd 

 at Winona, Ont., is undoubtedly this species. It causes a withering of the leaves some- 

 what like the Brown Rot, but the fruit is not affected nor has the under surfaco 

 of the leaf the downy api)earance of the Brown Rot. The leaves on thy 

 vines at Winona had the burnt appearance which is peculiar to many leaf 

 blights. The patches on the leaves indicating the disease, are large and irregular 

 in outline. These patches become quite dry and will break from the 

 leaf verj' easily. The spores are borne on the under surface of the leaf on 

 slender filaments and are produced in large numbers during damp weather. 

 This disease lives over the winter in the fallen leaves. It has not received very much 

 attention but it weakens the vines and prevents the full development of the fruit. 

 Spraying the vines, as for Black Rot, should prove quite effectual with this disease. 



COYER CROPS. 



English Horse Beans and Rape. — In the report for 1903. experiments in the 

 use of the English Horse Beiin and Hairy Vetch were described. It was shown that 

 Horse Beans and Hairj- Vetch sown in rows 2S inches apart had given very satisfactory 



