THE PRINCIPAL DISEASES OF CITROUS FRUITS IN FLORIDA. 
By WALTER T. SWINGLE and HERBERT J. WEBBER. 
INTRODUCTION. 
It is the purpose of this bulletin to give, in as brief and concise a 
manner as possible, an account of some of the principal diseases of 
citrous fruits, especially those occurring in Florida. The following 
are the diseases which we will endeavor to describe and illustrate: 
Blight, die-back or exanthema, scab or verrucosis, sooty mold, foot rot 
or mal-di-gomma, and melanose. 
The diseases of citrous fruits have received more or less attention from 
the Department, through the Division of Vegetable Physiology and 
Pathology, since the year 1886. In 1891 Prof. L. M. Underwood was 
sent to Florida to make a preliminary study of this subject. Later the 
Same year one of the writers, with Dr. Erwin F. Smith, was sent to 
Floridae to carry on further studies, especially on blight, and the fol- 
lowing spring the former returned to continue the work. In the fall of 
1892 a slightly increased appropriation enabled the Department to 
Station both writers regularly in Florida. A laboratory especially 
erected for the purpose was donated by the citizens of Eustis, Fla., and 
this point was made our headquarters. Since the completion of the 
building both laboratory and field investigations have been carried on 
continuously, with highly gratifying results. Melanose, an entirely new 
disease, has been studied and remedies for it discovered. Satisfactory 
remedies or preventives have also been found for all the other diseases 
mentioned above, foot rot being the only one which could be said to be 
under control when the work was commenced. Much information has 
been collected in relation to the causes of the various diseases and 
their effects on the plants attacked. 
It is gratifying to record here the uniformly kind and generous treat- 
ment we have received from the fruit growers of Florida, without whose 
aid and support much of the work here summarized would have been 
impossible. 
BLIGHT. 
This disease, also called wilt and leaf curl, is found only in Florida, 
and so far as known at present is incurable. Nearly all citrous fruits 
are liable toit, but in different degrees. Trees grown on light hammock 
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