PLANT DISEASES DUE TO FUNGI. 45 



rough callus is formed around the wound. In the early autumn the 

 fungus may be seen in the crevices in the form of tiny white cushions, 

 which ultimately bear on their surfaces the minute conidia or fruit. 

 In the following spring the bright-red perithecia may be seen on the 

 edges of the wound. Young apple trees examined in February were 

 literally covered with these, indeed to such an extent that they were 

 all taken up and burned. 



PREVENTIVE AND REMEDIAL MEASURES. 



Care should be taken to see that all wounds, after pruning or 

 cutting away diseased branches, are coated over with gas tar. 



Spraying, after the leaves have fallen, with i Ib. of sulphate of 

 iron, i oz. of sulphuric acid and i gallon of water, will destroy the 

 conidia and their hyphae. 



Grafts should not be taken from diseased trees. 



All prunings and dead diseased branches should be at once burnt 

 and not allowed to lie about the orchard. 



Attention should be directed to hedgerows where hazel or any 

 of the above-mentioned trees are present, as these are frequently a 

 source of infection. 



CURRANT-LEAF SPOT. 



Septoria ribis, Desm. 



This disease, often termed Currant Rust, has been particularly 

 prevalent during the past season on Black Currants. 



The first indications of the disease are small irregular brown or 

 purplish-brown spots on the leaves. Covering these spots are a 

 number of minute dots, which, if examined with a magnifying glass, 

 will be found to be slightly raised above the surface of the leaf, each 

 having a minute opening or pore at its apex. These are the con- 

 ceptacles, and contain the long, thread-like, curved spores. 



Usually this disease is treated with indifference by growers, but 

 as it makes a considerable drain upon the plant, they usually suffer 

 by reduced crops the following season, and if not attended to the 

 vitality of the plant becomes so reduced that in a season or two little 

 if any fruit is borne. 



