Articte XIII.—Further Tests of Dry Sulfur Compounds for the 
Control of the San Jose Scale. By Westry P. FLtint. 
INTRODUCTION 
During the season of 1919 a series of experiments for the control 
of the San Jose scale was conducted in two orchards on the west side of 
the state. The object of these experiments was to make a thorough test, 
under field conditions, of several widely advertised dry sulfur com- 
pounds intended for the control of the San Jose scale. A description of 
these experiments and the results have been published in Experiment 
Station Circular No. 239, this work being conducted by W. S. Brock, 
of the Horticultural Department of the University of Illinois, and the 
present writer. During the season of 1920 the work in the Quincy 
orchard was continued and slightly enlarged, but that in the Barry or- 
chard was abandoned for lack of funds. 
The dry sulfur compounds, especially the dry lime-sulfurs, have 
several advantages over the commercial lime-sulfur solutions, for orchard 
use. Some of these advantages are that the dry material is not subject to 
leakage ; does not deteriorate with freezing; is much cheaper to ship and 
easier to haul; and is much handier to work with, especially for the 
small orchardists. 
For a better understanding of these experiments the description and 
results of the work done in 1919 are first given in full. 
LocATION AND CONDITION OF ORCHARDS 
The orchards selected for the experiments are near Barry, Pike 
county, and Quincy, Adams county. 
The orchard in Pike county is located one and one-half miles west 
of Barry and contains about forty acres of mature Ben Davis trees. 
The block selected in the Barry orchard adjoins an Osage hedge which 
was probably the original source of the scale infestation. The trees 
nearest the hedge were incrusted and, untreated, would almost certainly 
have failed to survive the season of 1919. At a distance of two hundred 
feet from the hedge the infestation was not quite so serious, but many 
of the limbs were incrusted. The plots were arranged to include each 
degree of infestation, and were as nearly uniform as possible. 
The orchard near Quincy, situated two miles east of the city, on 
the farm of Wm. Hausemann, consisted of six acres of seventeen-year 
