34 2 Diseases of Truck Crops 



trouble, conspicuous on stalks, fruit, and leaves. On 

 the leaves it is manifested as a mottling of yellow 

 areas on the tissue between the veins. The unequal 

 growth of tissue causes the leaves to warp and grow 

 unevenly. In severe cases the normal leaflets are 

 replaced by a filform or fern-like structure (fig. 64 a), 

 with a striking dissected form. The blossom of the 

 diseased plant usually drops off, and the few setting 

 fruits are small and deformed. 



Southern Wilt 



Caused by Pseudomonas solanacearum Ew. Sm. 



Southern wilt has a wide distribution. As its 

 name indicates, it is generally found in the more 

 southern States. It is generally severe in Texas, 

 Alabama, Georgia, Mississippi, North and South 

 Carolina, Florida, Maryland, Virginia, New York, 

 and Connecticut. 



Symptoms. Infected plants usually wilt rapidly 

 without losing their green color. In large leaves, the 

 main axis is bent downward in a drooping way. 

 With the young plants the stems and foliage also 

 droop and shrivel. The vascular system of such 

 plants is browned, indicating the presence of the 

 causative organism within. In cutting across a 

 freshly wilted stem, a dirty white to brownish white 

 slime that is not sticky is seen to ooze out. In soft 

 and rapidly growing plants, the whole pith is often 

 converted into a watery slime. In tomato and egg- 

 plants the disease seldom attacks the fruit but is 



