CITRUS MELANOSE AND ITS CONTROL 
43 
SPRAYING EXPERIMENTS IN 1923 
Spraying experiments were continued in 1923 at Orlando on seed- 
ling orange and grapefruit trees and at two other points in the 
State on grapefruit. Thirty-five plots were sprayed at Orlando with 
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Fig. 9. — Quantities of copper remaining In spray residue on citrus leaves during a 
3%-month period. Five spray mixtures were used, and these were applied three 
times to certain plots (A, B, C, D, E), and once to other plots (A', B\ C, D\ E'). 
The first application was on April 14 
various copper compounds or with lime-sulphur solution for the 
control of melanose. 
In former years the only oil emulsions used were prepared with 
soap, but this season the soap-oil emulsions were used in comparison 
with kaolin-oil emulsions (27). Since no appreciable difference in 
effects could be noted between the two types of emulsion in Bordeaux 
mixture, a discussion of their respective merits is not given. 
The first application was made as early as April 3 and the last 
was made on June 15, the plots receiving from one to three applica- 
tions respectively. The materials used, dates and number of appli- 
cations, together with the degree of melanose control obtained on the 
sprayed plots, are given in Table 10. 
