198 Cucumber and Melon Leaf Blotch. 



To test the possibility of this means of introducing the 

 disease, an empty box that had contained diseased cucumber 

 leaves sent to Kew for determination, was placed over a young 

 vegetable marrow plant that was growing under glass ; within 

 three days every leaf was destroyed by the disease. Another 

 marrow plant growing in the open and subjected to similar 

 treatment did not contract the disease. 



Preventive Measures. 

 If the foliage is fairly hard the disease cannot assume the 

 dimensions of an epidemic, and even if it appears it can be kept 

 well in hand by spraying. To accomplish this end a fair supply 

 of air should be admitted so that the atmosphere is not con- 

 stantly saturated with moisture. It is wise to spray in anticipa- 

 tion of the disease, using a solution of potassium sulphide — 

 two ounces to three gallons of water, adding two ounces of 

 soft soap. 



It is very important that the under surface of the leaves be 

 thoroughly wetted with the solution. 



If the disease is present, the soil should also be drenched 

 with the solution. 



Diseased leaves should be removed and burned before they 

 decay and fall to the ground. 



After a diseased crop has been removed the soil should be 

 thoroughly drenched with a solution of " Jeyes' Fluid," in the 

 proportion of an ounce to a gallon of rain water. 



As to the danger of infection arising from spores being 

 conveyed in packing cases as recorded above, no suggestions 

 can be offered ; nevertheless the matter is one claiming the 

 attention of cultivators, and as the wholesale mixing up of 

 such hampers appears to be the rule rather than the exception, 

 it is probable that many diseases other than the one under 

 consideration have by this means been first introduced to a 

 new locality.* 



Description of the Figures. 



1. Cucumber leaf shewing the disease in an early stage of development. Natural size. 



2. Portion of a diseased patch of leaf shelving the fruiting coiidition of the fungus. 

 Mag 11. 40. 



3. Rife Conidia. Magn. 400. 



* Copies of this article in leaflet fcrm may be obtained free of charge and post 

 free on application to the Secretary, Board of Agriculture, 4, Whitehall Place, 

 London, S.YY. Letters of application so addressed need not be stamped. 



