The most important wilt diseases are Fusarium wilt, which is 
prevalent throughout the warmer regions of the United States, and 
verticillium wilt, which is most serious in California and Utah. 
Bacterial wilt causes some loss in the South. 
Defoliation by leaf spot diseases reduces yields and exposes the 
fruit to sunscald. Some leaf spots affect only the foliage and 
stems, while others also cause rot of the fruit. Septoria leaf 
spot and grey leaf spot are the chief diseases affecting only the 
leaves. Leaf mold causes minor loss. Early blight and late blight 
cause spotting of the leaves and rots of the fruit, although late 
blight is the most injurious as a fruit rot. This disease is 
always a major threat to tomatoes. Most of these diseases are 
widespread in humid areas east of the Continental Divide. Leaf 
mold, however, is prevalent chiefly in the South Atlantic States, 
and gray leaf spot has only recently spread from the South into 
the North Central and Middle Atlantic States. 
Some frvit rots are caused by fungi that do not affect the leaves. 
The most important is anthracnose, which is destructive in tomatoes 
grown for processing in humid sections. Soil rot and buckeye rot 
cause minor losses. 
Virus diseases affect tomatoes wherever they are grown. The 
tobacco mosaic virus causes some reduction in yield in most fields. 
Curly top virus is often very damaging to tomatoes west of the 
Continental Divide and sometimes causes loss in areas adjacent to 
the eastern slope of the Recky Mountains. Its occurrence is re= 
stricted because it is transmittec by a leafhopper present only in 
semiarid areas in the West. Other virus diseases cause minor losses. 
Blossom-end rot, a nonparasitic disorder due to high temperatures 
and lack of soil moisture, causes some injury throughout the United 
States. ; 
Losses from Fusarium and verticillium wilts can be reduced by use 
of resistant varieties and crop rotation. No varieties resistant 
to bacterial wilt are available. Seed treatment and the application 
of fungicides are the chief means of contrelling leaf spots and 
fruit rots, although there are varieties with some resistance to 
certain of these diseases, Virus diseases are not yet adequately 
controlled. Losses from nonparasitic diseases can he reduced by 
gocd cultural practices. 
Tomatoes, for Fresh Market 
The diseases causing the most serious losses of fresh-market 
tomatoes are generally the same as those damaging the processing 
erop. However, late blight is more dameging to the fresh-market 
crop, because much of it is growm in humid coastal areas of the 
South Atlar:tic and South Central States,where this disease is more 
Sica 
