CITRUS MELANOSE AND ITS CONTROL 35 
only general conclusions should be attempted at this stage of the 
development of melanose control. To take any one plot or even any 
one grove as a standard for comparison may prove misleading, but if 
the plots and groves are taken collectively the results point in the 
same general direction each year. 
SPRAYING EXPERIMENTS IN 1917 
The attempt to control melanose by sprays, made in 1917 by the 
Office of Fruit Diseases, following the freeze of February of that 
year, is the second recorded effort to control melanose by sprays. 
A small preliminary spraying experiment was conducted at Orlando, 
Fla., in an old seedling orange grove that had been severely damaged 
by the freeze. Bordeaux mixture, ammoniacal solution of copper 
carbonate, commercial lime-sulphur solution, and self-boiled lime- 
sulphur solution were used. The first application was made on 
April 12 and 13, the second on April 26, 27, and 28, and the third on 
May 10 and 11, followed by an application of insecticide on June 12 
to prevent excessive scale increase. 
This grove, previously damaged by foot rot, was so severely in- 
jured by the freeze that there was little or no bearing wood left, and 
the small crop that did set developed from late May and June 
bloom. All of the deadwood was left in the trees as a source of 
infection for the new succulent growth which came on during the 
spring and summer months. The sprayings were not carried on 
through the summer as had been planned, therefore the applica- 
tions that were put on gave only a partial protection to the vege- 
tative growth and little or no protection to the fruit that set in 
June. The fruits on all of these sprayed plots were severely affected 
by either rust-mite russet or the " ammoniation " that frequently 
develops on trees suffering with foot rot; these conditions were so 
prevalent that it was practically impossible to determine with ac- 
curacy the degree of melanose infection on fruits. 
The results of these preliminary tests showed that there was a 
marked reduction of melanose on vegetative parts on the plots that 
received Bordeaux mixture, but this was confined to the growth 
that took place during April and May. Melanose control on the 
plots sprayed with ammoniacal solution of copper carbonate was 
decidedly less pronounced, whereas those that received lime-sulphur 
solution had only a slight control if any at all. The plots that 
received one or two applications of ammoniacal solution of copper 
carbonate followed by one or two applications of sulphur compound 
were about as severely injured as the plots that received three appli- 
cations of lime-sulphur solution.* "Ammoniation" was much more 
prevalent on the checks and sulphur-sprayed trees than on those 
that received copper sprays. 
The rainy periods at Orlando, Fla., during the spring months 
of 1917 are shown in Figure 4. From this it is evident that there 
was not sufficient rainy weather during March to result in much 
melanose infection, and, as April was very dry, little or no infection 
took place. May also was very dry, but a moderate amount of 
infection developed during the first 10 days of the month. Begin- 
ning about the middle of June, the rainy season was accompanied 
by heavy melanose outbreaks. 
