iSS 



Apple "Scab" or "Black Spot." [june, 



" blistered " part, such as is shown at Kb in Fig. 6, it will 

 present the appearance seen in Fig. 8. At (a) we see some of 

 the cells of the wood ; seated on these is the cushion-like 

 mass of fungus spawn (b) which forms the " blister," and 

 covering its surface on the outside is a layer of dark-brown 

 spores (c). 



Any of these spores on being blown or carried to the leaves 

 or young fruit in the spring will immediately infect them and 

 produce the appearance shown in Figs, i to 4. 



During the past two seasons I have examined a number of 

 orchards and plantations with the object of ascertaining what 

 varieties of apples are susceptible as regards the young 

 wood. I have found scab-infested wood on the following 

 varieties : — Cox's Orange Pippin, Lord Sufheld, Ecklinville 

 Seedling and Yellow Ingestre or Summer Pippin — all severely 

 attacked ; t Wellington, Cox's Pomona, Warner's King, Glad- 

 stone, Councillor and White Transparent — less severely. 



According to my experience, the young wood of " Cox's 

 Orange Pippin " is almost invariably scab-infested if the 

 disease is in the neighbourhood. I have known instances 

 where young trees of this variety bearing scab-infested 

 wood have been sent out of nurseries. In rare cases I have 

 found a few of the weaker shoots actually killed by the disease ; 

 consequently it must be reckoned as one of the most susceptible 

 varieties as regards its wood. The wood of " Lord Sufheld, " 

 too, is very susceptible ; I have known cases where it has 

 become so scab-infested — the bark peeling off' in flakes — 

 that the owners have grubbed the trees, thinking them per- 

 manently ruined. 



As regards its direct effect on the young wood, however, apple 

 scab is not a serious disease except in the case of very severe 

 attacks on a few specially susceptible varieties. The chief danger 

 arising from the presence of " scab "-diseased wood is that the 

 pest thus persists on the trees through the winter months, 

 with the result that apple orchards and plantations which 

 have suffered for several seasons from " scab " are often 

 never wholly free from the disease at any time of the year. 

 In these cases the life-history of the fungus is as follows : — 

 In the spring the spores blow from the diseased wood to the 

 young leaves and the fruit as it is formed, then when the 



