April, ’24] 
snapp: paradichlorobenzene and peach borer 
255 
paradichlorobenzene for long exposures and large doses for short ex¬ 
posures. For the long exposure tests one-half, three-fourths and one 
ounce doses were allowed to remain around the trees for periods of three, 
four and six weeks, and also over winter. For the short exposure tests, 
one and a half, two, and two and a half ounce doses were exposed to the 
trees for periods of four, eight and twelve days. 
The results of these experiments indicate that under normal conditions 
the large doses exposed for short periods are not as effective as the 
smaller doses exposed for four to six weeks. The three-fourths ounce 
dose as well as the one ounce dose gave almost perfect control of the 
borer when exposed to young peach trees for four weeks. In nearly 
every case the control was one hundred per cent. The control from 
the one-half ounce dose averaged about 87.5 per cent. The control 
from large doses exposed for four, eight or twelve days varied between 
fifty-five and ninety per cent. 
Three separate examinations for tree injury from the various treat¬ 
ments were made on all the trees. The first was made about six weeks 
after the application, the second during the following spring, and the 
final one during mid-summer of the following year. No injury resulted 
from the use of the various doses around three, four and five year old 
trees during 1921 and 1922 when normal weather conditions prevailed 
in Georgia. However, during the fall of 1923 very abnormal weather 
conditions occurred in central Georgia, causing rapid action from the 
paradichlorobenzene crystals and an unusual resultant effect on young 
peach trees, which should be of special interest to those engaged in 
paradichlorobenzene investigations elsewhere. 
Paradichlorobenzene is placed around peach trees in Central Georgia 
between October 10 and 15. During the month of September 1923 a 
precipitation deficiency occurred which caused the soil to be exceedingly 
dry when the material was put out in October. During the three 
weeks following the application, practically no rainfall occurred. A 
local weather station six miles from where the paradichlorobenzene 
experiments were conducted reported only a trace of rainfall for the 
entire month of October 1923, which was the smallest amount recorded 
for any October at that point during the last 32 years. The normal 
October precipitation in Central Georgia is about three inches. There¬ 
fore, a drought occurred before the paradichlorobenzene was applied in 
1923, and continued for three weeks following the application. 
The soil temperature during October 1923 was abnormally high in 
Central Georgia. The mean soil temperature from sun rise to sun set 
