Bean Diseases 



III 



lings may decay and the result will be a very poor 

 and uneven stand. Under drier conditions a better 

 germination is obtained. The disease also works on 

 the older plants, forming irregular spots. When 

 their root system is attacked, affected plants become 

 yellowed and wilted by daytime, but slowly revive 

 at night. Should the air become muggy by over- 

 watering and high temperatures, infected plants ap- 

 pear as though they have been drenched with hot 

 grease, the leaves having a burned appearance. The 

 injured plants then seem to make a desperate at- 

 tempt to produce new foliage, which in turn becomes 

 affected; the pods cease filling, and ripening is very 

 uneven. 



In carefully examining diseased seed, it is found 

 to be yellowed and shriveled; or, in light cases of 

 attack, covered with irregular yellow blotches. On 

 the leaves, the trouble appears as watersoaked spots 

 which later become amber colored. The cankers on 

 the stems somewhat resemble the canker produced 

 by Colletotrichum lindemuthianum. 



The Organism. Fseudomonas phaseoli Ew. Sm. 

 is a short rod, rounded at both ends, and motile by 

 means of polar flagella (fig. 15, d and e.). It lique- 

 fies gelatin slowly, coagulates milk, and produces no 

 gas. For methods of control, see Anthracnose, p. 112. 



SCLEROTINIA RoT 



Caused by Sclerotinia lihertiana Fckl. 

 Sclerotinia rot is a disease which attacks snap 



