SPRAYING PLUMS AND CHERRIES. 215 
use their judgment as to whether the first application may be safely 
omitted. Where peach scab is the chief trouble, and brown-rot and 
curculio are of only minor importance, as may be the case in some of 
the Allegheny Mountain districts, satisfactory results may be had 
from two applications, namely, the first with self-boiled lime-sulphur 
and arsenate of lead four to five weeks after the petals fall, and the 
second treatment of the above schedule with self-boiled lime-sulphur 
alone three to four weeks later. These two treatments, if thoroughly 
applied, will control the scab and brown-rot, especially on the early 
and midseason varieties, and will materially reduce curculio injuries. 
Even one application of the combined spray made about five weeks 
after the petals fall would pay well, although this is recommended 
only for conditions where it is not feasible to do more. 
SPRAYING PLUMS AND CHERRIES. 
The first important tests of arsenicals in the control of the curculio 
were made on plums and cherries. In 1887 Mr. W. B. Alwood, work- 
ing under the direction of the entomologist of this department, made 
some limited tests on the grounds of the Ohio Agricultural Experi- 
ment Station, spraying Green Gage plum trees with Paris green at 
the rate of 1 pound to 50 gallons of water. Fully 50 per cent of the 
foliage and much of the fruit fell from the trees as a result of the 
treatment. No definite conclusions were drawn from the experiment. 
May 17 of the same year 17 cherry trees were also sprayed with Paris 
green, 1 pound to 50 gallons of water, and the results in this instance 
also were not fully determined. 
During the same year Prof. A. J. Cook in Michigan sprayed 4 plum 
trees May 18 with Paris green at the rate of 1 tablespoonful to 6 
gallons of water. “No trees were kept for comparison, and no definite 
conclusions were thus to be drawn. During 1888 Prof. H. Osborn, 
then an agent of the Division of Entomology, carried out in lowa 
some thorough spraying experiments, usi#® 11 plum trees of several 
varieties, leaving 10 trees unsprayed as a check. London purple was 
used at the rate of one-half pound to 100 gallons, applications being 
made June 1 and 11. Concerning results, Prof. Osborn states: 
Combining the entire count of all varieties, and we have for the sprayed trees a 
final of 32.48 per cent punctured, or stung, and 5.71 per cent containing larvee, against 
a final of 41.86 per cent stung and 10.39 per cent containing larvee for the check trees. 
During the same year Prof. Weed in Ohio began a series of tests of 
arsenicals on cherry and plum, which were continued during 1889 
and 1890, during which latter year the work was carried out on a 
commercial basis in a plum orchard of 900 trees in the fruit districts 
along the south shore of Lake Erie. These careful experiments of 
Prof. Weed clearly showed that a considerable benefit from spraying 
was to be derived and were altogether the most extensive and com- 
plete heretofore presented. 
