MARKET DISEASES OF FRUITS AND VEGETABLES 33 



Like russeting, sunscald affects only the appearance of the pods. 

 In sunscald the seed coats at times are affected, but there is no loss 

 of keeping quality or of viability. 



(See 124, 125, 126.) 



WATERY SOFT ROT (SCLEROTINIA ROT) 

 (Sclerotinia sclerotiorum (Lib.) DBy.) 



Watery soft rot frequently causes serious losses in green beans and 

 peas that are harvested following wet weather. It is often particu- 

 larly damaging to southern beans shipped in late winter and early 

 spring. The affected pods show water-soaked green to greenish-tan 

 lesions of various sizes and shapes, and usually a surface growth of 

 white cottony mold. In advanced stages of decay the mold spreads 

 from pod to pod, enmeshing them to produce the so-called "nests" of 

 moldy pods in the hampers during transit. Although low tempera- 

 tures (40° to 45° F.) retard the development of decay somewhat, 

 they will not entirely control the growth of the fungus. Experi- 

 ments have shown that this type of decay will develop from % 

 inch to over 1 inch lengthwise of bean pods in less than a month 

 when these are held continuously at 32°. Visible decay has been 

 observed to develop in inoculated green beans in 15 days at 32°, 

 in 11 days at 35°, in 9 days at 42°, in 6 days at 46°, and in 4 days 

 at 54°. For a complete discussion of this disease see Celery, Watery 

 Soft Rot, page 56. 



(See 117, 127, 128, 203.) 



YEAST SPOT 



(Nematospora phascoli S. A. Wingard) 



Yeast spot so far seems to be of rather localized distribution, hav- 

 ing been reported on lima bean in only a few States. The disease 

 affects the marketability of the shelled lima beans by rendering them 

 unsightly. It also is responsible for a reduced yield by causing 

 premature death of seeds or by preventing seeds from growing to 

 normal size in the pod. 



The seeds alone are affected, consequently pods that appear per- 

 fectly healthy may contain badly diseased seeds. The seeds within 

 the pod may be attacked at any stage of development, but greater 

 damage is done if they become infected before they are half-grown. 

 Dark-brown, irregular, sunken areas are produced, but usually the 

 seed coats remain unbroken. The affected tissues are grayish brown 

 and granular in texture. The pathogen is a yeast that grows best 

 at a temperature of about 85° F., and makes very little growth at 

 65°. 



Apparently the organism gets to the seeds through wounds, for in- 

 oculation experiments have proved successful only when the pods and 

 seeds were punctured. The first symptoms are evident within 2 or 

 3 days after inoculation, and prominent lesions are formed within 

 a week. 



No control measures have been worked out. 



(See 59, 15^) 



303920° — 41 5 



