Tomato Diseases 185 



color, and a local drying which produces white spots 

 with a dry, peppery appearance. Such fruit is unfit 

 for the market. 



Control. In houses where sunburn is prevalent it 

 is advisable to have the house shaded and to plant 

 varieties that have a dense foliage. 



Mosaic 



Cause unknown. 



A lengthy discussion on mosaic has already been 

 given on p. 102. Mosaic on tomato is a common field 

 and greenhouse trouble, conspicuous on stalks, fruit, 

 and leaves. On the leaves it is manifested as a 

 mottling of yellow areas on the tissue that causes 

 the leaves to warp and grow unevenly. In severe 

 cases the normal leaflets are replaced by a filiform or 

 fern-like structure, with a striking dissected form. 

 The blossom of the diseased plant usually drops off, 

 and the few fruits that are set are small and de- 

 formed. 



Southern Wilt 



Caused by Fseudomonas solanacearum Ew. Sm. 



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. Upon cutting across a 

 freshly wilted stem, one observes that a dirty white 



