ment of this disease, and it is during such seasons that it spreads with 

 great rapidity. Last season was a characteristic one in this 

 respect, so that whether the coming summer be dry or wet it may 

 be expected that with the crop of seed, (spores) now on hand we 

 must be prepared to fight the disease, as it will surely be more or 

 less prevalent. 



The appeai'ance of the scab on the apple is too well known to 

 need a minute description. When a thin section of the diseased 

 portion of the fruit is examined by the aid of a microscope, Prof. 

 Galloway-^ says that "a cluster of short brownish threads is 

 seen arising from a darker mass of roundish cells, ' which are 

 seated directly upon the healthy tissue of the fruit or the leaf, us 

 the case may be. The free ends of the threads often bear pear- 

 shaped bodies of nearly the same colour as the supporting threads. 

 The pear-shaped bodies are the spores of the fungus, and it is 

 through their agency that the parasite is propagated. The brownish 

 threads serve merely as supports for the spores, while the dark 

 mass of tissue constitutes the body of the fungus, or, if I may so 

 express it, the root, branches and leaves. When full grown the 

 spores separate readily from their supporting stalks, and being 

 exceedingly light, are easily wafted from place to place by currents 

 of air. In this way they reach healthy fruit and leaves, and if the 

 proper conditions of moisture and heat are present they quickly 

 germinate, by sending out slender tubes, which bore their way into 

 the leaves or fruit, and ultimately give rise, just beneath the 

 cuticle or skin, to dark masses of cells, like those already des- 

 cribed. At first this mass of fungous tissue is entirely beneath the 

 cuticle, but as the former continues to grow the latter is ruptured, 

 and it is then that another crop of stalks and spores are formed. In 

 this way the fungus contmues its development throughout the 

 growing season, the crops of spores formed in the autumn living 

 over winter on the old leaves, fruit and 3'oung branches." And 

 thus we have a stock of seed (spores) for next year's crop, which 

 gei-minate, as already stated, when favourable conditions are found. 

 Just as soon as the leaves begin to form in the spring they are 

 attacked by the disease, and what is true of the leaves is also true 

 of the fruit, spots being sometimes noticeable on the latter when 

 little larger than peas. This emphasizes the statement that early 

 treatment is a prime essential towards successful results. 



* (Jalloway, Bulletin 59, Mich. Experiment Station. 



