1907.] 



Cherry Leaf Scorch. 



335 



-entail much trouble and considerable expense. But the neglect 

 of undertaking this operation, though costly, means the 

 disappearance of the cherry orchards of Kent in a very few 

 years/' In a few cases where growers followed this advice 

 an immediate cessation of the disease resulted. 



Prof. Percival, in his article* on the disease, attributed the 

 visitation to the exceptionally dry seasons experienced about 

 that time. With regard to remedies, Prof. Percival dismissed 

 the method of the collection and burning of the diseased 

 leaves as impracticable, and wrote " growers of cherries must 

 be content to wait for the advent of climatic conditions more 

 suited to vigorous growth than those of the last two or three 

 seasons, during which the fungus has become prevalent." 



In 1906, when appointed to the newly created post of 

 mycologist at the South-Eastern Agricultural College at Wye, 

 I found that the disease still persisted in many of the 

 orchards where it had occurred in 1900-02, and also that fresh 

 areas had become affected. 



Since the remedy of the collection and burning of the 

 diseased leaves secures the eradication of the disease in a district 

 only if carried out rigidly over the whole of the affected area, 

 and since the necessary energy and co-operation on the part of 

 growers to carry out this work was unfortunately not to be 

 looked for, other means had to be devised. It was obvious, 

 too, that as the disease had persisted in some orchards in certain 

 districts for fifteen consecutive years, during which time the 

 trees had been rendered practically useless, growers could not 

 be advised merely to wait for more favourable seasons. 



There remained the expedient of spraying. In 1906 I carried 

 out spraying experiments with the fungicide known as Bordeaux 

 mixture, when it was found that the present disease yields 

 readily to such treatment. 



Before describing these spraying experiments it will be well 

 to give a brief account of the life-history of the fungus which 

 causes cherry leaf scorch and of the characteristic features of 

 the disease. 



Cherry orchards attacked by this fungus can be at once 

 recognised in the winter and early spring months by their 

 peculiar appearance, due to the fact that the dead leaves 



* Jour 11. South- Eastern Agric. College, No. xi, p. 83 (1902). 



