130 Bulletin 313 



Cercospora apii Fr. — On the leaves of celery, parsnips, etc. 

 Causes a serious leaf-spot disease. Spots on any part of the leaf, 

 mostly at apex, at base of main serrations, or at side of basal portion 

 of the leaf ; varies in character with location and humidity, yellowish, 

 becoming large and ashy-gray, frequently surrounded by a halo of 

 yellow, often becoming confluent. Spots on petioles greenish-gray, 

 elongating in the direction of the axis. Conidiophores on both sur- 

 faces of the leaf, fascicled, light brown, subundulate, non-septate or 

 1- or 2-septate, 40-100.4 x 4-7.5 fx; conidia hyaline, or light brown, 

 clavate or slightly curved towards apex, 3-16 septate, 50-215.7 x 

 4-7.7 fi. 



(Written from notes by Mr. W. S. Krout.) 



780. Infected leaflet of celerJ^ 781. Conidia, 1/12. 



Cercospora armorace^ Sacc. — On leaves of horse-radish. Causes 

 pale spots on both surfaces of leaves. Conidiophores short, simple, 

 septate, 30-40 x 5 /x ; conidia long and tapering, hyaline, many septate 

 v/hen mature, 100-120 x 5 ju. 



782. Part of infected leaf of horse-radish. 783. Conidiophores, 1/12. 784. 

 Conidia, 1/12. 



Cercospora eeticola Sacc. — On the leaves of the beets and 

 chard. Causes brownish, purple-bordered spots which develop ashy 

 centers witli age. Conidiophores fasciculate, short, erect, non-sep- 

 tate, 35-55 x 4-5 fi; conidia long, filiform, obclavate, multi-septate, 

 hyaline, 75-200 x 3.5-4 fi. 



785. Part of infected leaf of beet. 786. Conidiophores and conidia, iyi2. 

 787. Conidia, 1/12. 



