'20 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Cherry-leaf Spot. 

 Coryneum Bcijcrinckii (OucL), PI. XI. fig. 22. 



The attacks of this fungus have been recognised in at least two 

 different ways— in one as a leaf parasite and in the other as the main 

 cause of gummosis. Under the former aspect it has been found on 

 ( lu rry, Peach, Apricot, Almond, and Plum. In the spring the young 

 leaves are found to exhibit red or rosy spots on the under surface as well 

 as on the young shoots. Later on the tissue in such places turns brown 

 and dies, when the fungus appears in minute black dots which are 

 grouped on the dead spots, and in these the conidia are produced. 



The dots, or pustules, are at first developed beneath the cuticle, 

 forming compact discs, which are at length erumpent. The conidia are 

 seated upon a kind of cushion or stroma, crowded together, and are 

 oblong, pale olive, with three septa (28-32 x11 - 13 n) on hyaline 

 pedicels. 



Later in the season a second form of fruit appears, and ultimately it 

 i3 believed that another form appears, which has been called Ascospora 

 Beijerinchii, wherein the spores are enclosed in asci. 



This disease has been recognised in the Netherlands as well as in 

 Britain. 



No remedies have yet been pronounced successful, but probably spray- 

 ing at the earliest period when there is any indication of the presence of 

 the disease may be effectual. 



Sacc. SijU. iii. 4058 ; Mass. PL Dis. 294. 



Gummosis. 



Gummosis is not by any means a new or uncommon disease, which 

 has been attributed to various causes and latterly to the presence of a 

 fungus under the name of Coryneum Beijerinckii. Whatever may be the 

 cause the remedy has not yet been found. 



It is contended on behalf of those who advocate the Coryneum theory 

 that the disease may be communicated by inoculation ; but the presence 

 of mycelium or even more advanced fungoid growth in the morbid spots 

 is extremely probable, apart from any active participation in the disease. 

 I nlortunately the disease is common enough, but the presumed fungus is 

 BO rare that only one or two persons have professed to have seen it in this 

 country. It must be remembered also that the species of Coryneum 

 otherwise known are saprophytes, and the presumption is strong against 

 i lie assumed cause of gummosis. 



Ma-sec contends that the cause of gummosis in Prunus japonica may 

 be trace 1 to the action of Cltulosjtori uni cpiphyllum. 



'» 1 11 commended that diseased branches should be removed or collar 

 pruning r< orted to. The soil around the trees may be treated with 

 quicklime on the surface to destroy conidia in the soil. 



Q vrd. Ohron. Mar. 20, 1884 ; 1891, fig. 68; Kew Bulletin, 1899, p. 1, 

 plate Ma PI Dis. 806, fig. 82; McAlpine Fung. Dis. p. 67. 



