254 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 17 
ment. During the 1921 season a quarter of a million pounds of para- 
dichlorobenzene were used for borer control by the peach growers in 
the Southeastern States. During the following season (1922) about the 
same amount was used. Reports, however, show that during the fall of 
1923, five hundred thousand pounds of the material were used in the 
Southeast. These figures are indicative of the increased interest in 
this new method of borer control, and of the satisfactory results that 
have been obtained from its utilization in commercial peach orchards. 
Blakeslee’s work prior to 1920 showed that the chemical could be 
safely used on trees six years of age and older for the control of the 
peach borer. In certain cases, however, he noticed injury to trees 
younger than six years of age that were treated with paradichlorobenzene. 
In view of the fact that the peach borer is often very destructive in 
young orchards, and since it would be highly desirable, if possible to use 
the chemical on peach trees of all ages, extensive experiments have been 
conducted in Georgia by the Bureau of Entomology during the last three 
years to ascertain whether the new method of borer control could be 
extended to trees of all ages under climatic conditions in that latitude. 
For these experiments peach trees ranging from one to five years of 
age were used. Studies were also made of the effect on the trees from 
not opening up the mounds and removing unspent crystals six weeks 
after the application. The effectiveness of late fall, early winter, and 
spring applications of paradichlorobenzene were tested in another series 
of experiments. The laboratory work included a sktufy of the effect of 
temperature and moisture on the rate of evaporation of paradichloro¬ 
benzene and what influence these factors have on the mortalitv of the 
j 
peach borer from the toxic gas. 
No attempt will be made in this paper to give detailed accounts of the 
results obtained from any of the work. An effort will be made to 
merely point out the most important things revealed as a result of the 
work, and to report on the action of the chemical during a season when 
a precipitation deficiency is accompanied by abnormally high tempera¬ 
tures. (I wish to give due credit to Mr. C. H. Alden of the U. S. Bureau 
of Entomology who has assisted the writer with all of the paradichloro¬ 
benzene work in Georgia during the last three years.) 
Results from the Use of Paradichlorobenzene on 
Young Peach Trees 
During the past three years several thousand peach trees ranging 
from one to five years of age have been treated with both small doses of 
