DISEASES AND PESTS OF PLANTS. 



23 



" RUST." 



There is a true fungus-rust which attacks the leaves, but this has not been noticed 

 here. What commonly goes by this name is a rusty or orange-red spotting of the 

 outer leaf-stalks where they are in contact with the soil. Probably due to local infec- 

 tion by soil organisms, and preventible by using boards for blanching. 



CHERRY. 



BROWN-ROT. 



This is chiefly destructive to the sweet cherry. This is chiefly grown, however, 

 in the Dry Belt, where the disease is not serious, if present at all. In the wet 

 climate of the Lower Mainland, in seasons which favour the disease, it is often not 

 possible to control it profitably, especially as the conditions which contribute to its 

 severity also cause other damage, such as the splitting of the fruit. An account of 

 the disease and its control will be found under " Plum." 



Fig. 4. Brown-rot on sweet cherries. The lower figure shows a series 

 of different stages in the development of the disease. 



GUMMOSIS. 



The cherry, in common with other stone-fruits, is very liable to suffer from this, 

 the sweet cherry especially so. The cell-walls break down and are changed into gum, 

 which exudes and dries in masses on the bark. Often this follows wounds or frost- 

 injury, but it may be spontaneous, as in wet seasons or situations, or where growth 

 has been forced. In the case of gumming from wounds, where these are of any size, 

 they should be cleaned out and disinfected. The bacterial guuunosis due to a specific 

 organism, and which is so destructive in Oregon, has not been observed here. 



