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JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



scab. Often the young fruits are attacked as soon as they are formed 

 and the petals have fallen away. 



The mycelium of the fungus creeps along beneath the cuticle and 

 soon produces short erect brown threads on the dark spots which cause 

 the velvety appearance of the surface, and ultimately the apex of each 

 thread is capable of producing a single spore, or conidium, which is also 

 coloured and oval, egg-shaped or pear-shaped, or attenuated towards each 

 end, and sometimes divided by a septum into two unequal cells. 



These spores, or conidia, germinate rapidly in water or in a moist 

 atmosphere. Spots may sometimes be seen covered with the fallen 

 conidia in various stages of germination. It has been found that they 

 will germinate most readily in pure water of a temperature of about 

 50° Fahr., and within about eight hours. 



Another method of reproduction has been intimated by the United 

 States Department of Agriculture, to the effect that the individual cells 

 of the mould under certain conditions will push out germ tubes, which 

 develop into new individuals ; a method " which may be roughly 

 compared to that by root cuttings in some of the higher plants." 



Latterly it has been affirmed that the diseased leaves which lie on the 

 ground in winter develop in that condition a higher or more complex 

 form of fruit, in which the sporidia, or reproductive bodies, are produced 

 within asci, as in other sphariaceous fungi, and are extruded in spring 

 when they are capable of germinating and infecting fresh leaves. The 

 name applied to this final condition is Vcnturia inaqualis. 



We have only now to indicate the methods which have been recom- 

 mended to combat this disease, whether occurring on Apple or Pear trees. 



In early spring before the buds have commenced to expand, spray the 

 trees thoroughly with a solution of sulphate of iron, using one pound of 

 the iron sulphate to each gallon of water. 



As soon as the fruit has set, apply the Bordeaux mixture (sulphate of 

 copper and lime), or one of the modified preparations of eau celeste 

 (sulphate of copper and ammonia). 



If the weather should be such as to favour the development of the 

 " scab," a third application should be made two or three weeks after the 

 second, using the same material. 



In storing the fruit for the winter especial care should be taken to 

 separate all the fruits showing any signs of the " scab " from those which 

 are smooth and healthy, and they should all be kept in rooms or cellars 

 free from moisture. 



When the spots have been found to develop themselves on the leaves 

 too late to be checked, all diseased leaves should be collected and burnt, 

 so as to prevent the dispersal of the spores. 



All dead leaves should be carefully collected when fallen from the 

 trees and burnt at once before the ascigerous fruit is produced and a new 

 element of infection comes into existence. 



Badly infected trees are a great source of danger in an orchard, and 

 would be better condemned and removed to save the rest. 



For reference the following authorities may be consulted : Journ. 

 B.H.S. xxviii. 1903, pp. 6, 14, PI. X. fig. 3 ; Gardeners Chronicle, Novem- 

 ber 28 } 1885, ngs. 155, 156 ; Massee's Plant Diseases, 302, figs. 80, 81 ; 

 U.S.A. Depart. Agr. 1887, p. 341 ; Depart. Agr. Victoria Bull 3, 1902. 



