434 DISEASES OF CULTIVATED PLANTS 



warted, black lines, 1-2 mm. diam., conidia oozing out in 

 black tendrils, elliptic-oblong, pale olive, 5-9 X 3-4/* ; conidio- 

 phores long, branched, curved. 



If the disease is neglected it spreads rapidly, and the tree 

 soon dies. If diseased parts were cut out on their first 

 appearance, perhaps the disease might be checked, or at all 

 events delayed. 



GLOEOSPORIUM (Desm.) 



Spore-clusters formed under the epidermis, bursting through 

 at maturity. Spores elongated, continuous, hyaline, borne at 

 the tips of slender sporophores. 



Generally on living leaves and stems. The well-known 

 G. ribis (Mont.) has been proved by Klebahn to be a conidial 

 form of an ascigerous fungus, Pseudopeziza ribis (Kleb.) ; 

 other forms of Gloeosporium have also been associated with 

 higher ascigerous fungi. 



The genus Colletotrkhum only differs from the present in 

 having coloured, spine-like bodies present in the spore-clusters. 



Raspberry spot ( Gloeosporium venetum, Speg.) is the 

 cause of a widespread disease to raspberry canes. The leaves 

 are also sometimes attacked. The injury first appears under 

 the form of small, reddish spots, which gradually increase in 

 size and often encroacn on each other, forming irregular 

 blotches, which when old become pale coloured and bounded 

 by a dull red margin. The spore-clusters are minute, 

 clustered, rather prominent; spores almost cylindrical, 

 7-8X2 - 3/i. On raspberry, Rubus idaeus, and cloudberry, 

 R. chamacomorus. 



When the disease is observed infected canes should at 

 once be cut out, as the spores are formed in great abundance 

 and infect neighbouring canes. Spray with dilute Bordeaux 

 mixture if the plants are not yet in bloom, if they are, use 

 potassium sulphide. When the disease has existed, spray 

 during the winter with sulphate of iron solution. 



Peach leaf blotch {(iloeosporium cydoniae, Mont.) often 

 causes irregularly shaped brown patches to appear on living 

 leaves of the peach {Cydonia vulgaris). As a rule the disease 

 spreads rapidly, all the leaves being attacked, when they wilt 

 and turn yellow ami fall prematurely. The spore-clusters are 



