74 
THE NATIONAL NURSERYMAN 
THE USE OF SULPHUR WASHES ON THE FOLIAGE 
OF FRUIT TREES. 
Sulphur Sprays in Summer. 
By P. J. PARROTT, New York State Experiment Station, Geneva, N. Y. 
The introduction of the lime-sulphur wash marks a rfew 
period in the history of spraying in this State. It was only 
in 1902 that experiments demonstrated that this spray was 
adapted to our climatic conditions, and that it could be 
safely recommended to our fruit growers as a promising 
insecticide. Its extensive use at the present time is a strk- 
ing demonstration of the progressive spirit of our fruit 
growers. There is probably no other spray that has such a 
cleansing effect on fruit trees or has such a wide range of 
usefulness in the treatment of orchards for injurious insects 
and plant diseases. While it is an efficient insecticide and 
fungicide, it is not a cure-all. With the increasing use of 
the sulphur wash, fruit growers should clearly understand 
its field of usefulness, and the conditions under which this 
spray may be advantageously employed. 
Chief Use of Wash is for Treatment of Dormant 
Trees. 
The sulphur wash is principally employed for the treat¬ 
ment of the San Jose scale during the dormant season. 
For this purpose it is not surpassed. It is a cheap, safe and 
an efficient spray, and for these reasons it meets the needs of 
many fruit growers. It has also been shown that applica¬ 
tions that have been made for the scale, while trees were 
dormant or as buds were breaking, have also proven of con¬ 
siderable value for other orchard pests. Experiments have 
demonstrated that this treatment efficiently controls the 
leaf blister-mite, which is now so abundant fin many apple 
orchards in western New York. While there is a difference 
of opinion among entomologists as to the exact effects of the 
sulphur wash on the oyster-shell scale and the scurfy louse, 
evidence is accumulating, which tends to show that spraying 
with the sulphur wash for successive years during the dor¬ 
mant season cleans the trees of these pests. Pear growers, 
who have used this mixture for several years, believe that 
the applications have proven of some value in preventing 
injuries by the pear psylla. The effectiveness of this mix¬ 
ture for insects other than those mentioned has not been so 
clearly indicated.. Of the utility of a sulphur spray for 
orchard diseases, less is known. It has proven an efficient 
remedy for the peach leaf curl; and spraying in early spring 
with a sulphur wash is now an established practice in many 
areas where this fruit is grown on a commercial scale. The 
treatment of apple trees with a sulphur wash has had some 
effect on apple scab, but its actual value for this arid many 
other fruit diseases has not yet been determined. The 
reputation of the sulphur wash as a combined insecticide 
and fungicide it will be seen, has been largely based on its 
effectiveness against those species of insects and fungous 
diseases which are amenable to winter . spraying, or to 
treatment that is made not later than when the buds are 
breaking and the tips of the young leaves are making their 
appearance. 
Sulphur Sprays for Summer Treatment. 
The home-made wash, prepared after the common 
formula, cannot be used as a summer spray because of its 
destructiveness to the foliage. It is for this reason that 
treatment with this wash is restricted to the dormant sea¬ 
son. Moreover, spraying for the scale during the summer 
is usually considered inadvisable because of the habits of 
this insect, and of the difficulty of making thorough applica¬ 
tions on account of the interference of the foliage. But as 
sulphur possesses both fungicidal and insecticidal proper¬ 
ties, it has been suggested that a weaker strength of a 
sulphur wash might be used, which would be safe to foliage 
and of some value in controlling various diseases and other 
insects than the scale. 
Efforts to Compound a Safe Sulphur Spray for 
Foliage. 
Many attempts have been made to devise a formula for a 
sulphur wash that could be safely employed for summer 
spraying. The first step that naturally suggested itself was 
to use the winter wash, much diluted with water. Experi¬ 
ments soon showed that preparations containing as little as 
one pound of sulphur and one pound of lime to fifty gallons 
of water were sometimes destructive to foliage and of little 
value for the scale. Present experience indicates that 
preparations of the lime-sulphur wash, by boiling, even 
when much diluted with water, have a very limited field of 
usefulness as summer sprays. With the introduction of the 
commercial preparations of the lime-sulphur wash, efforts 
were then directed to determining the utility of these sprays 
as substitutes for bordeaux mixture for summer applications. 
Special interest has been aroused in the probable use of 
these sprays on trees in foliage by the experiments of Prof. 
A. B. Cordley of the Oregon Experiment Station, who used 
the lime-sulphur solution at strengths of one gallon to fifteen 
or twenty gallons of water without injury to the leaves, and 
succeeded in controlling apple scab without causing spray- 
injury to the fruit. The promising results that attended 
his efforts prompted similar experiments in other States. 
At the Geneva Station tests Were made of various commer¬ 
cial preparations of the lime-sulphur wash and of the home¬ 
made concentrated mixture at different strengths, varying 
from one gallon of the concentrated solution to twenty 
gallons of water, to as weak as one gallon of the solution to 
Continued on page 77. 
