MARKET DISEASES OF FRUITS AND VEGETABLES 31 



taminated with this fungus and spotting results if moisture and tem- 

 perature conditions favor its development. Usually, small brown 

 spots one-sixteenth to one-eighth inch in diameter are produced on 

 the seed coat, but under humid conditions they may become larger 

 and show an olivaceous color due to a superficial growth of the 

 causal fungus. In advanced stages of decay greenish-brown granular 

 spore masses are formed over the larger spots and on removal of the 

 seed coat brown spots may be found on the seed (cotyledons). 



Experiments have shown that spotting may be controlled for a week 

 by a temperature of 40° F. ; at 32° beans are safe from spotting for 

 about 2 weeks. Where it is feasible to use solid carbon dioxide (dry 

 ice) as a refrigerant the increased carbon dioxide content of the air 

 assists greatly in retarding development of the causal fungus. Beans 

 held in an atmosphere containing 25 percent or more of carbon 

 dioxide will develop little or no spotting, and the flavor and texture 

 of the beans are not injured. 



Tests of various washing solutions have shown that a 4-percent 

 solution of chlorinated lime will give excellent control of seed 

 spotting if the pods are washed in this solution before the seeds are 

 shelled. 



(See 67.) 



SEED STICKINESS 



Although many kinds of bacteria may cause a sticky condition of 

 the surfaces of shelled green lima beans under transit and storage 

 conditions, it appears that Pseudomonas ovalis Chester, Achromobac- 

 ter coadimatwm (Wright) Bergey et al, and an organism similar to 

 A. lipolyticum' (Huss) Bergey et al. are the most common causes of 

 this trouble. These soil organisms contaminate the seeds during the 

 shelling process. When temperature and moisture conditions favor 

 their development on the seed coat a sticky or slimy condition results. 



Prompt refrigeration is an effective control measure for the pre- 

 vention of stickiness. A temperature of 32° F. will prevent the 

 development of stickiness for 2 weeks; at 40° good control may be 

 expected for about a week. 



Stickiness may also be prevented by washing the shelled beans 

 for 1 minute in a 30-percent solution of ethyl alcohol and allowing 

 them to dry for a short time before packing them for shipment or 

 storage. 



Washing the pods in a 4-percent solution of chlorinated lime before 

 shelling has been found to give good commercial control of stickiness. 



(See 67.) 



SOIL ROT iRHIZOCTONIA STEM AND POD ROT) 

 (Rhisoctonia solani Kiihn; Corticium vagum Berk, and Curt.) 



Soil rot affects the root, stem, and pod of the bean. In the field 

 it causes damping-off, stem rot, and pod rot; in transit it often 

 causes severe decay of pods. The fungus spreads readily by contact 

 under moist conditions and is one of the organisms responsible for 

 the "nesting" of beans. This term merely implies that within a 

 hamper or other package there is a mass of decaying snap beans held 

 together by a copious growth of mycelium. 



