126 Bulletin 313 



Macrosporium cucumerinum E. & E. — On the leaves of cucum- 

 bers and muskmelons. Causes orbicular, sometimes confluent, rusty- 

 colored or whitish spots about 3-4 mm. in diameter. Conidiophores 

 solitary or fascicled, brown, flexuous, somewhat branched, 1-8 sep- 

 tate, 57-140 X 5-9 fi in length, 5-9 /x in diameter at base and 4.6 ix in 

 diameter at tip ; conidia numerous, club-shaped, brown, multi-sep- 

 tate, 57-81 X 11-24 /A, with long beak having a hyaline tip. 



762. Infected leaf of Cttcumis melo. 763. Coiiidium, 1/12. 



Macrosporium herculeum E. & M, — On leaves of turnips, 

 horse-radish and other crucifers. Causes gray to brown spots. 

 Conidiophores erect, fexuose, few septate, 70-80 x 5 /*; conidia 

 brown, multi-septate, clavate, 139.8-225 x 18.2-23 ii. 



764. Spots on portion of turnip leaf. 765. Conidium, 1/12. 



Alternaria abutilonis* Speg. — On the leaves of Ahiitilon 

 abutilon. Causes irregular brown spots visible on both surfaces of 

 the leaf. Conidiophores branched, smoky to hyaline ; conidia club- 

 shaped, muriform, pale yellowish to smolcy, 5-7 septate, 50-9 x 

 10-15 fx. 



766. Conidium, 1/12. 



Alternaria brassic^ (Berk.) Sacc.^ — On the leaves of cabbage, 

 collards and other crucifers ; causing black mold. Conidia clavate, 

 5-11 septate, 50-60 x 12-14 fx. 



767. Conidia, 1/6, 1/12. 



Alternaria cucurbits Let.— On the leaves of cucumbers and 

 melons. Causes circular spots which frequently become confluent 

 and cover the entire leaf. Conidiophores short, straight, brown; 

 conidia multi-cellular, clavate, olive-colored, 60-68 x 8-9 /*. 



768. Conidia, 1/12. 



Alternaria solani (E. & M.) Jones & Grout. — On the leaves of 

 the potato and tomato. Causes brown, more or less circular, concen- 

 trically-zonated spots. Conidiophores septate, 50-90 x 8-9 fi; coni- 

 dia obclavate, brown, transverse septa numerous, longitudinal septa 

 few, beak long, hyaline, 145-370 x 16-18 /a. 



769. Infected potato leaf. 770. Germinating conidium, 1/12. 



*Syn. Macrosporium abutilonis. 



