MARKET DISEASES OF FRUITS AND VEGETABLES 19 



vegetables on the market. Among these the common bean, lima 

 bean, and garden pea are of greatest importance. 



Beans 



The pods or entire fruits of the wax and green pod varieties of 

 the common bean {Phaseolus vulgaris L.) generally are marketed for 

 table and canning purposes, whereas the lima bean {P. lunatus 

 L., var. m-acrocarpus Benth.) is sold either in pods or shelled. 

 Marketability of the snap bean varieties is determined primarily 

 by tenderness, crispness, good color, and freedom from blemishes 

 and decay; in the case of lima beans filling the pods is of primary 

 importance. 



Toughness and poor color may be due to old age. The pods take 

 on a poor color and become flabby, tough, and stringy when they 

 become overmature on the plants and the seeds become large and 

 hard. Too long an interval between picking and consumption also 

 may lead to poor color, flabbiness, and toughness of the pod. 



Lack of crispness of the pods may be due to wilting of immature 

 pods either before or after picking. In the former case, drought 

 or diseases of the plant may be the cause; in the latter, excessive 

 drying in the field, in the packing house, or in transit may be re- 

 sponsible, especially if the beans were picked when very young. 



A number of diseases, such as bacterial soft rot, cottony leak, 

 gray mold rot (see Peas, Gray Mold Kot, p. 37) , rhizopus rot, russet - 

 ing, and watery soft rot, only rarely cause loss in the field but are 

 exceedingly important in the later stages of distribution and market- 



Many diseases that decrease production by killing or weakening 

 the plants also directly affect the pods. The most important of 

 these are: Anthracnose, bacterial blight, bacterial wilt, downy mil- 

 dew, pod blight, powdery mildew (see Peas, Powdery Mildew, p. 39), 

 sclerotium rot, soil rot. and rust. The plants and pods are also 

 affected with heat injury, hopperburn, and sunscald. 



There are several bean diseases that seriously curtail production 

 by attacking the plant but do not affect the pods directly. Wilting, 

 toughness, and underdevelopment of pods may be indirect effects of 

 fusarium root rot {Fusarium> solani (Mart.) var. irbartii (App. et 

 Wr.) Wr. f. 3 Snyder and other species), of mosaic,, of leaf spots 

 (Cervospora canescens Ell. and Mart., Gercospora enienta Sacc, and 

 Phyllosticta phaseolina Sacc), of ozonium root rot {Phymatotrichum 

 omnivorum (Shear) Dug.), of ashy stem blight (Macrophomina 

 phaseoli (Maubl.) Ashby), of root knot (Heterodera marioni (Cornu) 

 Goodey), or of root rot (Thielawiopsis basicola (Berk.) Ferraris). 



(See 59, 60, 61, 62, 63, 70, 73, 76, 81, 82, 86, 107, 108, 114, 119< 

 123, 132, 133, 136, 139, UO, 157, 158.) 



ANGULAR LEAF SPOT 



(Isariopsis griseola Sacc.) 



This peculiar leaf spot is found on snap beans and has also been 

 reported on peas. Sometimes the pods are attacked, thus making the 

 disease a direct market factor. In cases of severe spotting of the 



