562 



THE FUNGI WHICH CAUSE PLANT DISEASE 



Key to Genera of Melflnconiaceae-Scolecospora 



Conidia aUantoid 1. Naemospora. 



Conidia bacillar to filiform 

 Conidia fasciculate at the apex of the 



conidiophores 2. Tiichodytes. 



Conidia solitary 

 Masses white or pale, f oliicolous ; conidia 



filiform 3. Cylindrosporium,p. 562. 



Masses gray or dark, usually rami cole; 



conidia falcate 4. Cryptosporium, p. 564. 



Masses bright-colored, saprophytic; 



conidia falcate 5. Libertella, p. 564. 



Cylindrosporium Unger 



Acervuli subepidermal, white or pallid, disciform or subeffuse; 

 conidia filiform, continuous, hyaline, straight or curved. 



About one himdred species of 

 parasites, several of them of con- 

 siderable economic importance. 



C. mori Berl. on Morus=Myco- 

 sphaerella morifolia. See p. 249. 



C. castanicolum (Desm.) Berl. 

 on Castanea=Mycosphaerella macu- 

 liformis. See p. 249. 

 C. padi Karst.'"^'-"" 

 Hypophyllous; spots angular, sub- 

 fuscous; acervuli subepidermal caus- 

 ing elevations; conidia curved, 

 cylindric, 48-60 x 2 m; conidio- 

 phores minute, produced in great abundance. 



This is the cause of the most common, familiar, widespread and 

 destructive shot-hole disease of the cherry and plum. When on 

 the peduncles the fruits are dwarfed and ripen imevenly. The 

 diseased leaf tissue usually falls away, resulting in "shot-holes." 

 Acervuli abound. 



Arthur found a Phoma associated with this fungus and later 

 asci in the same pycnidia. He believed these forms all con- 



FiG. 379. — C. padi, section of acer- 

 vulus. After Pammel. 



