154 ORANGE CULTURE IN FLORIDA. 



a study of this disease in 1886,* attributed it to a 

 parasitic fungus (a species of Cladosporium], whose 

 growth in the tissues of the leaf produced the dis- 

 tortions and sapped its vitality. Our own observa- 

 tions confirmed these conclusions. 



4. Remedies, In the paper above alluded to 

 Professor Scribner makes the following recommen- 

 dations for spraying mixtures : (a) A solution of 

 potassium bisulphide, one half ounce to the gal- 

 lon ; (b) liquid grison ; (c) one half pint carbolic 

 acid and one pound of glycerine added to ten gal- 

 lons strong soap-suds. 



We could not leain that these remedies cr any 

 other treatment had been attempted in any of the 

 orange regions visited. 



V. LEAF-SPOT. 



1. Nalure of Disease. On certain leaves of the 

 orange, both wild and sweet, faded spots appear, 

 varying in shape, but mostly rounded or oval, and 

 in size from one eighth of an inch to an inch in 

 diameter. As the disease progresses, these spots 

 become grayish brown and dead, and covered on 

 one or both surfaces with a series of minute black 

 points, which contain the fruit of the fungus, which 

 is the cause of the disease. 



2. Distribution. This disease was found at only 



* Bulletin Torrey Botanical Club, xiii., 181-83 (Octo- 

 ber, 1886). 



