104 



THE CANADIAN HORTICULTURIST, 



According to Prof. Penhallow, of 

 Quebec, 90 per cent, of the fruit of the 

 Walbridge apple was worthless from the 

 scab last year in that province. And 

 now, with great dismay, we notice that 

 it is attacking our favorite apple, the 

 beautiful Northern Spy. 



THE FUSICLADIUM 



is a parasitic fungus — that is, it belongs 

 to that class which preys upon living 

 substances, and not upon dead matter, 

 like the mushroom ; and in order that 

 no confusion of terms may arise, Mr. 

 Crawford advises horticulturists the 

 world over to call it, not spot, rust, 

 scab, or mildew, but Fusicladium. 



The plant, for such it really is, is so 

 minute, that it can only be examined 

 by a good lens, and the seed spores are 

 so very tiny that Prof. Crawford tells 

 us it would take 3,200, side by side, to 

 reach one inch. How these seed spores 

 are preserved through the winter, is 

 still an open question, but such minute 

 bodies would easily be carried about in 

 the air in early spring, and settling upon 

 a leaf or young apple begin quickly to 

 germinate in favorable weather. The 

 spore sends out a slender tube, which, 

 according to Prof. Trelease, of Wiscon- 

 sin, is probably able to pierce the skin 

 of the leaf. In case of the apple itself, 

 he thinks it might find entrance through 

 one of the little dots, for over it the 

 outer skin is often s|)lit. As soon as 

 it sTfiins entrance, this tube begins to 

 l>ranch out, and tlnis form the myce- 

 lium, or that part which corresponds to 

 roots, and this, as it grows, burst open 

 the epidermis, or outer skin, and throws 

 up little brown threads, or stems. These 

 grow up to a certain height, and each 

 produces a single spore. 



We copy from the plates in Mr. 

 Crawford's Report the illustrations 

 shown below, which may help our 

 readers to undei'stand the growth of this 

 fundus. 



Fig. 1 represents a section of the 

 apple scab magnified 200 diameters ; 



— Section of an apple scab. 



a section of an apple leaf 



Fio. 1 



and Fig. 2 



through a very small spot, also magnified 



200 diameters. The spots upon the apple 



Fig. 2.— Very small leaf spot. 



leaf appear on the surface, somewhat as 

 is shown in Fig. 3, and soon the part 

 tui-ns black, or, if badly affected, the leaf 



Fig. 3.— Leaf affected bj- Fusicladium. 



drops off. Last summer the apple tree 

 leaves blighted so seriously in the Nia- 

 gara District as to almost strip the trees, 

 and much of the fruit fell with them. 

 Many attributed this to the use of Paris 

 Green, but it was particularly observed 

 by the wr-iter that the leaves shrivelled 

 and fell just as badly in orchards that 

 had not been treated with the poison, 

 so that it could not have been due to 

 its use. This occurred in the month of 

 June, when the apples were about as 

 large as marbles. Further investigation 

 will determine whether it is entirely 

 owing to the spread of Fusicladium. 



REMEDIES PROPOSED. 



All remedies so far tried in Australia 



