1146 Investigations into Silver Leaf Disease. [Mae., 



the proceedings at the Ministry's Cattle Testing Station at Pir- 

 bright, where cattle intended for export are tested for tuber- 

 culosis, or immunised against red water prior to export to 

 South America, East Africa, etc., aud also gives an account 

 of the work carried out at the Ministry's laboratory. Under 

 the latter heading, no less than 4,052 specimens were examined 

 for the purposes of diagnosis of scheduled diseases, and 235 

 others for non-scheduled diseases, and 913 litres of anti-swine- 

 fever serum were prepared during the year, and 390 litres dis- 

 tributed for use in outbreaks during the same period. In regard 

 to vaccination against epizootic bovine abortion, 24,520 lb. of 

 vaccine were prepared and distributed for the inoculation of 

 animals in affected herds. 



The Report is published by H.M. Stationery Office, and is 

 to be purchased through any bookseller, or direct from the 

 Stationery Office, price 2s. 6d. 



****** 



The havoc wrought by Silver I eaf disease in plum growing- 

 districts is unfortunately only too well known to growers. The 

 Investi ations f un o us nas killed thousands of trees and 



-r * nas rendered it almost impossible for 

 into Silver Leaf , u . .p.., . * , 



Disease growers to cultivate v ictoria and Czar plums 



in some districts. It is not too much to 

 say that unless some adequate measures of control are adopted, 

 the very existence of the plum growing industry in this country 

 is threatened. The damage caused by the disease, however, is 

 by no means confined to the plum. Mr. F. T. Brooks of Cam- 

 bridge has recently reported that the fungus is now attacking 

 apple trees, particularly Early Victoria, Lord Grosvenor, Lord 

 Suffield and Newton Wonder. Mr. Brooks also states that he 

 has found the disease on pear trees, which had hitherto been 

 considered to be immune from attack. 



For some years past, Mr. Brooks has been carrying out inves- 

 tigations into the disease, and more recently in conjunction with 

 Mr. Hatton, the Director of the East Mailing Research 

 Station, has been undertaking experiments to determine the 

 relative susceptibility of the common varieties of plum when 

 worked on different stocks. It will necessarily be some few years 

 before anv definite results can be obtained from these experi- 

 ments, but from observations made in orchards, it does appear 

 that the stock is capable of influencing the tree to a marked 

 degree. One case which came under observation in a Hunting- 

 donshire orchard is particularly convincing. This orchard is 



