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JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 13 
are less active; consequently, they are not as easily killed, and further¬ 
more the poisonous material may also have some effect on the peach 
trees. 
President W. C. O’Kane: The next paper is “Dust versus Spray 
for the Control of Sour Cherry Pests in Pennsylvania,” by J. G. Sanders 
and D. M. De Long. 
DUST VERSUS SPRAY FOR CONTROL OF SOUR CHERRY 
PESTS IN PENNSYLVANIA 
By J. G. Sanders and D. M. DeLong, Harrisburg, Pa. 
The northern portion of Erie County, Pa., contains approximately 
ten thousand acres of fruit orchards and vineyards. In this area the 
growing and marketing of sour cherries is a considerable factor. Due 
to local conditions adjacent to Lake Erie, the usual pests affecting sour 
cherry, such as curculio, slug and leaf spot disease, are more or less 
destructive, varying considerably from year to year. In this Lake 
area, as was noted in similar conditions in Wisconsin, the cherry slug is 
unusually destructive throughout a strip four to five miles in width—• 
adjacent to the Lake. 
The damage from curculio, slug and leaf spot was exceptionally 
serious in 1918, and following requests for help from the growers, a 
series of experiments was carried on during the summer of 1919 to 
determine the relative value of dust and spray mixtures for pest con¬ 
trol. Sour cherry trees six years of age, comprising four blocks, 12 
trees in width and 34 in length—with a check plot 3 by 12 trees, were 
selected at one end of a large cherry orchard. The test plots were 
bounded by vineyards on the east, north and west, while the continua¬ 
tion of the orchard was to the southward. The remainder of the 
orchard—not included in the test—was sprayed three times by the 
owner with commercial lime-sulfur solution, 1 to 40. The prevailing 
winds in this section are from the southeast, blowing diagonally from 
the check and the remainder of the orchard, across the treated plots. 
It will be noted that the first plot was treated with Bordeaux mixture, 
3-3-50, with 1 pound of arsenate of lead added; the next plot was 
treated with hydrated lime, sulfur and arsenate of lead dust, 50-45-5; 
the next with lime-sulfur spray, 1 to 40; and the next with sulfur- 
arsenate of lead dust 90-10. Applications to all test plots were made 
first on May 31, 1919, after the petals had fallen; second on June 13; 
and third on July 19, just after the fruit picking. No dormant spray 
had been applied to any block of this orchard. 
The advantages of the dust over the spray—from the standpoint of 
application—are evident in that the time of application alone, dis¬ 
regarding the time required for mixing, was more than double in the 
