BORDEAUX-OIL EMULSION". 13 
GROVE C, FORT MYERS, FLA 
1918 TREATMENTS. 
In the spring of 1918 a grapefruit grove at Fort Myers was sprayed 
for the control of citrus scab. Essentially the same materials were 
used there as in the Winter Park grove that year. Very hard arte- 
sian water was used. The first application was made March 15 and 
the second April 15. Scab did not appear in the grove, nor was 
spray-burn observed. 
On July 30 those plats sprayed with sulphur compounds had very- 
few scales, even less than the unsprayed trees. Plats sprayed with 
copper compounds were very badly infested with the purple scale. 
Plats receiving plain Bordeaux mixture were perhaps the worst in- 
fested, while plats sprayed with the mixture plus one-third of 1 per 
cent of oil, with Burgundy mixture, or ammoniacal copper-carbonate 
solution were somewhat less severely infested. No doubt this was 
due to the addition of an insecticide to the Bordeaux mixture, the 
relative solubility of Burgundy mixture, and the temporary effective- 
ness of ammoniacal copper-carbonate solution. All plats having a 
severe infestation of scale were sprayed with 1 per cent of oil on 
July 30, and little or no further injury followed. 
GROVE D, ORLANDO. FLA. 
1920 TREATMENT. 
A part of the orange grove designated as grove D, at Orlando, Fla., 
was sprayed with 3-3-50 Bordeaux mixture plus one-half of 1 per 
cent of oil at intervals of a week, beginning April 1 and ending July 
29; another part was sprayed at intervals of two weeks, and still 
another part at intervals of four weeks, with the same materials, for 
the control of citrus melanose. Soft lake water was used in making 
these sprays, which controlled the disease. Slight spray-burn was 
found, which will be discussed later. 
In spite of these weekly applications of a weak insecticide in the 
combined spray, the purple scale became very abundant, and it was 
necessary to make an application of 1 per cent of oil as emulsion on 
August 13. Another application of oil emulsion was made in late 
October to control the dictyospermum scale. 7 The sprays were ap- 
plied so frequently as to result in the practical elimination of all the 
entomogenous fungi, white flies, and scale insects. 
Rust mites. — Rust mites did not appear on the plats sprayed at 
weekly intervals with Bordeaux-oil emulsion, owing probably, to the 
very frequent applications of oil, which is more or less effective in 
preventing a heavy infestation of rust mites. The thick coating of 
Bordeaux mixture no doubt also prevented the rust mites from feed- 
ing on the leaves and fruits. Rust mites developed abundantly on 
the other plats, indicating that the oil emulsion did not prevent the 
development early in the season. They were present in great abun- 
dance in late May on plats sprayed at 2-week and 4-week intervals. 
To check their increase an application of barium tetrasulphid was 
made on May 25 on the 2-week plat and one-half of the 4-week plat. 
The results of counts made in this grove are given in Table 4. 
7 Chrysomphalus dictyospermi Morgan. 
