BORDEAUX-OIL EMULSION. 5 
These findings were confirmed by O'Byrne's tests (6 and 7) of 
sprays for citrus nurseries and by his observation of the commercial 
use of this combination spray in bearing groves. 
Childs and Robinson, in an unpublished report of an investigation 
of the persistence of Bordeaux mixture and Bordeaux-oil emulsion, 
with particular reference to the control in Oregon of apple-tree 
anthracnose (Neofabraea malicorticis (Cord.) Jackson), conclude that 
Bordeaux mixture properly prepared possesses very marked adhesive 
qualities, that the proprietary sprays as a group have relatively low 
qualities of adhesion, and that Bordeaux mixtures, whether homemade 
or commercially prepared, are made more persistent by combining 
them with a good miscible-oil spray. It would seem that Bordeaux 
mixture combined with the dormant oil sprays used in the West, 
largely for the control of the apple leaf-roller (Archips argyrospolla 
Walker) and the San Jose scale (Aspidiotus perniciosus Comstock), 
should prove a valuable adjunct to the present spray schedule, 
since tests show that 40 per cent of the copper remains on the branches 
for a year and would doubtless have the effect of reducing the chances 
of infection by the apple-tree anthracnose fungus. 
The present report gives additional data on the preliminary spray- 
ing tests in Florida and the findings from later and more extensive 
trials in experimental plats and in commercial groves of citrus fruits. 
LABORATORY TESTS. 
During the winter of 1916-17 numerous laboratory tests were made 
with the various copper sprays to determine whether they could be 
mixed with the several oil emulsions and miscible oils then used in 
general grove spraying. After a few preliminary tests it was decided 
to concentrate on combinations of Bordeaux mixture with emulsified 
mineral oils. The oils in these tests were emulsified by different 
processes, and in some cases stabilizing materials, such as casein, 
milk powders, and starch, were added. The miscible or soluble oils 
of commerce were also tested, and both the stabilized and unstabilized 
emulsions as well as the miscible oils mixed readily with alkaline 
Bordeaux mixture. While the Bordeaux mixture underwent quite 
a change in general appearance, becoming grayish green in color, the 
precipitate did not settle as rapidly as that of plain Bordeaux mixture. 
After standing, little or no free oil came to the surface, indicating 
that the oil remained in suspension, probably in an emulsified state. 
More careful laboratory tests were made later with Bordeaux 
mixture containing various ratios of copper and lime, and measure- 
ments were recorded of the rapidity with which these precipitated 
materials settle. The Bordeaux mixtures in these tests were pre- 
pared by pouring together simultaneously the dilute blues tone 
solution and dilute limewater. The resulting mixture was agitated 
for 30 seconds before adding the oil emulsion, which was made 
according to Yothers's boiled-oil formula and used at the rate of 1 per 
cent of oil in the diluted spray. After the oil emulsion was added 
to the mixture the agitation was kept up for 10 seconds, when the 
Bordeaux-oil emulsion combination was poured into 100 c. c. grad- 
uated cylinders and readings taken at regular intervals thereafter. 
The results of these findings are shown in Figure 2 
