CHAPTER XXI. 



RUST ON THE ORANGE. 



flJST has been the cause of considerable annoy- 

 ance to the growers of the orange in Florida. 

 f The writer has for years been engaged in experi- 

 ments for the purpose of ascertaining, first, the 

 cause of, and then the remedy for, the rust. Some 

 years ago he reached the conclusion that the rust 

 was nothing more than the oxidized oil from the 

 skin spread over the surface. This discovery was 

 first made through the microscope, and afterward 

 confirmed by chemical tests. The cause of exuda- 

 tion of oil was first attributed to some peculiar con- 

 dition of the soil. Different remedies were applied 

 with the hope of getting rid of such matter as would 

 produce an excess of hydrocarbonates. Among 

 other things, caustic lime was applied broadcast 

 through the orangery. The rust disappeared for 

 two or three years, and again returned. Eighteen 

 months ago the writer's attention was called, by 

 Mr. W. C. Hargrove, of Palatka, to a microscopic 

 insect first noticed by Mr. J. K. Gates, and believed 

 by them to be the cause of the rust. 



This led me to investigate in another direction. 

 Knowing Mr. William H. Ashmead, of Jacksonville, 



