Bordeaux-Oil Emulsion Spray 
J. R. Winston and W. W. Yothers, U. S. Department of Agriculture, 
Orlando, Florida 
Bordeaux mixture, one of the standard 
spray compounds, is generally conceded 
to be the most effective all-round spray 
that has been devised for the control of 
plant diseases. Co-existing with its desir¬ 
able qualities there are several undesir¬ 
able features and for this reason numer¬ 
ous substitute materials have been ex¬ 
ploited or otherwise introduced from 
time to time. 
The experienced fruit growers of Flor¬ 
ida are too well acquainted with the va¬ 
rious sprays to need a discussion of the 
several types, especially their limitation, 
but for those who have taken up citrus 
growing more recently a few words of 
explanation may be justified. 
In general, the copper sprays, such as 
Bordeaux, Burgundy, and ammoniacal 
copper carbonate, mixtures possess fungi¬ 
cidal properties of considerable potency 
which kill beneficial fungi or those which 
cause insect diseases as well as those caus¬ 
ing plant diseases. They possess no ma¬ 
terial insecticidal values, consequently 
scale insects increase rapidly after such 
sprays are applied, unless proper insecti¬ 
cides are used following these applica¬ 
tions. This is especially true where Bor¬ 
deaux mixture is used for this material 
'Published by permission of the. Secre¬ 
tary of Agriculture. 
is effective over a considerable length of 
time. 
Sulphur sprays, for example, lime-sul¬ 
phur, soda-sulphur, and barium-sulphur 
solutions, possess both fungicidal and in¬ 
secticidal properties to a fair degree. 
They are much less effective, against fun¬ 
gi in general than copper sprays. The 
reaction of the sulphur compounds on 
fungi is milder than copper sprays and 
operate over a much shorter length of 
time. On the other hand, these sulphur 
compounds kill young scale insects and 
therefore these pests do not increase very 
rapidly following the application of such 
sprays. 
Because of the very serious scale infes¬ 
tation which is almost sure to follow ap¬ 
plications of copper sprays, most fruit 
growers select the sulphur compounds as 
a means of controlling citrus diseases. 
However, conditions for severe infection 
frequently arise which warrant the use 
of Bordeaux mixture. Heretofore, when 
such was the case, several additional ap¬ 
plications of oil emulsion were necessary 
in order to reduce the scale infestation to 
a normal level, thereby adding no small 
amount to the annual cost of spray ma¬ 
terials and their application. Aside from 
the scale and white fly increase., rust 
mites are known to become more abun- 
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