30 MISC. PUBLICATION 4 40, U. S. DEPARTMENT OF AGRICULTURE 



depends upon local conditions: therefore local authorities should 

 be consulted. 



(See 87, 88, 97, 100.) 



SCAB 

 (Elsinoe canavaliae Rac.) 



Although scab has not yet been found on beans grown in the 

 United States, it is known to occur in Central America and Mexico 

 and is one of the common and most destructive diseases of lima 

 beans in Cuba and Puerto Rico. Over a period of years the lima 

 beans imported from these localities have shown more or less spotting 

 by this disease. 



On the pods conspicuous red, brown, and maroon, swollen, oval 

 lessons varying in size from one thirty-second to one-half inch in 

 diameter are characteristic symptoms (pi. 7, E). The spots are 

 scattered irregularly over the pod, but they do not penetrate to 

 the seeds. However, badly spotted pods are injured in appearance 

 to such an extent that they are unmarketable, even though the seeds 

 within are healthy. 



(See 68,69, 101^,105.) 



SCLEROTIUM ROT (SOUTHERN BLIGHT) 

 (Sclerotium rolfsU Sacc.) 



As a seedling blight and stem decay of bean plants sclerotium 

 rot sometimes causes serious damage, but on the marketable pods 

 of snap beans it seldom is important. Under wet soil conditions 

 in the Southern States, bean pods that touch the soil or become 

 spattered with mud during rain may contract the disease. The 

 decay produced is watery, but not much change in color takes place 

 in the affected tissues. The best diagnostic symptom is the white, 

 silky fanlike mycelium growing over the surface of the pods, and 

 in advanced stages the presence of brown spherical (mustard-seed- 

 like) sclerotia. 



Sclerotium rot is also of minor importance as a semi watery decay 

 of carrots and garlic. This decay of these products has been ob- 

 served most often on the Chicago market in shipments from 

 Louisiana. 



Inoculation experiments with bean pods indicate that infection 

 will not take place at a temperature below 46° F. Consequently 

 temperatures of 40° to 45° in transit will check the extension of 

 old lesions and prevent the formation of new ones. 



(See 117.) 



SEED SPOTTING 



(Gladosporium h&rbwrum (I'ers.) Link) 



Shelled green lima beans frequently show an undesirable spotting 

 that greatly reduces their value by tin 1 time they reach the market. 

 Most of this spotting is caused by a species of Cladosporivm that 

 inhabits decaying vegetable matter and often blemishes the pods of 

 beans and peas. During the shelling process the seeds are con- 



