130 FUNGOID PESTS OF CULTIVATED PLANTS. 



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. 

 Unfortunately the disease is common enough, but the presumed fungus is 

 so 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 

 the assumed cause of gummosis. 



Massee contends that the cause of gummosis in Prunus japonica may 

 be traced to the action of Cladosporium epiphyllum. 



It is recommended that diseased branches should be removed or collar 

 pruning resorted to. The soil around the trees may be treated with 

 quicklime on the surface to destroy conidia in the soil. 



Gard. Chron. Mar. 29, 1884 ; 1891, fig. 68 ; Kew Bulletin, 1899, p. 1, 

 plate ; Mass. PL Dis. 306, fig. 82 ; McAlpine Fung . Dis. p. 67. 



WITCHES' BROOM OF CHERRY. 

 Exoascus Cerasi (Fckl.). 



Those peculiar malformations, which are known under the name of 

 witches' brooms, are not uncommon on various trees, and amongst them 

 the Cherry. Under these attacks the disease shows itself in the produc- 

 tion of dense tufts of branches, growing apparently from a central point, 

 and forming a bunch like a besom, which is very common on the Birch. 



This malformation is caused by the presence of a fungus similar to 

 that which causes the leaf curl of the Peach, and which appears a* a 

 hoary bloom on the branches. The vesicles, or asci, which contain the 

 sporidia are slender and club-shaped (30-50 x 7-10 /z), enclosing the 

 nearly globose sporidia (6-9 x 5-7/*). These asci are supported at the 

 base upon a distinct stem-cell (10-16 x 5-8 or 3-5 /*), which is divided 

 off from the ascus by a transverse septum. 



Known also in Germany, where it was first recognised and described. 



The only known remedy is to cut out the tufts and burn them. 



Sacc. Syll. x. 4734 ; Tubeuf, .Dis. p. 163, figs. ; Mass. PL Dis. 89, 358. 



CHERRY-LEAF SCORCH. 

 Gnomonia erythrostoma (Awd.), PI. XI. fig. 19. 



This disease sometimes makes it appearance in Cherry orchards in 

 great numbers and proves destructive to the crop. 



The leaves are attacked and soon present a scorched appearance, 

 withering, but hanging on the tree through the winter. Long slender 

 colourless curved conidia are produced, and in this condition it is known 

 as Septoria pollens. 



During the winter another and final stage is attained by the fungus 

 produced on the dead hanging leaves (Gnomonia erythrostoma). In this 

 condition the receptacles are immersed in the substance of the leaf, with 



