1920] A LiTTiiE Known Vetch Disease 73 



Forage Crop Investigations, Washington, D. C, to occur in South 

 Carolina, Georgia, Alabama, Mississippi, Louisiana and Tennessee. 

 Even though the disease was first collected in New York as long ago 

 as 1907, plant pathologists generally are not familiar with it and speci- 

 mens have, for this reason, not found their way into the several large 

 herbaria. Since the disease has not received a common name, and has 

 the appearance of an anthracnose, it is, in this account, designated as 

 false anthracnose. 



Appearance of the Disease 



False anthracnose can first be noticed during November and De- 

 cember when the plants are still small. A brownish discoloration 

 which completely girdles the stems of the seedlings is at this time 

 manifest. This discoloration begins near the surface of the soil and 

 extends upward. The main stem becomes dwarfed in consequence 

 and is soon surpassed in size bj' other shoots which develop below 

 the lesions. In other cases, the main stem is so severely involved that 

 it dies or the entire plant may succumb. The disease may be observed 

 at any time during winter but makes little progress until spring. It 

 then spreads rapidly upward upon the stem, producing characteristic, 

 short, dark-brown to blackish streaks, Fig. 25, which may remain 

 isolated or become so abundant as to quite uniformly discolor all of 

 the invaded portions. Young stem lesions are at first grayish in color 

 and their change through light brown to dark brown or black is due 

 to the pigmentation of the mycelium within the cortical cells. Young 

 stems are killed early in the season whereas older woody ones may live 

 to maturity. The leaves, including stipules, petioles and leaflets, are 

 successively^ involved, beginning with the lowermost. The lesions, 

 except upon the leaflets, are entirely similar in outline to those upon 

 the stems and pass progressively through the same changes in color. 

 Those upon the leaflets may remain minute and circular with a 

 tendency toward being most numerous along the principal veins or 

 may appear as elongated, dark streaks. Affected leaflets are pale 

 green in color, especially when several hundred spots develop upon 

 a single leaflet, and become markedh^ chlorotic before the lesions 

 attain their mature depth of color. Fig. 24. They eventually become 

 dry and fall off. 



The mature spots on the legumes or pods are so strikingly dis- 

 tinctive that there is no difficultv in distinguishing false anthracnose 



