April, ’24] 
chandler: paradichlorobenzene 
251 
were treated, and all severely injured. Most of the smaller larvae of 
Saperda Candida were killed, but the more mature specimens, working 
in the burrows, were still living. 
In September, 1921, I treated six <S-yr. old Transparent apple trees at 
Ozark, Ill., with % oz., P. D. B. A month later these trees were ex¬ 
amined. A total of 7 live borers and 7 dead were found. As in the 
case above referred to, the live borers were usually those deepest in 
the wood, and especially those that had worked highest up. No in¬ 
jury, however, was observed, either at that time or later. This may 
possibly indicate that injury to apples by P. D. B., under conditions of 
soil and climate similar to those of southern Illinois, may not be feared, 
and it is recorded here in the hope that it may be of some help to future 
investigators of the subject. 
Amounts to be Used on Old Trees 
Our usual recommendation has been to use ^ oz., for trees from one to 
five years of age, and I oz., for trees six years old or older. To ascer¬ 
tain the amounts needed on old trees, a portion of a 12 year old orchard 
was treated in Centralia, on Oct. 19, 1922, using 1 oz., \}4 oz., and 2 
oz., respectively, with the following results: 
10 trees, 1 oz. totalled 27 worms, 23 dead, or 85.5% kill. 
10 “ \y 2 “ “ 52 “ 47 “ “ 90.4% “ 
10 “ 2 “ “ 60 “ 59 “ “ 98.4% “ 
10 “ Check “ 101 “ 0 “ “ 
These data, altho from but one season’s work, indicate that it might 
be profitable to apply as much as 2 oz., of P. D. B., to trees of this age. 
Mr. Alvah Peterson : I would like to ask Mr. Chandler if he has had 
any experience in treating peach trees in the nursery with this material. 
Mr. S. C. Chandler: We have only tried it in the case of one or two 
trees. 
Mr. J. J. Davis : I might say that we have used Paradichlorobenzene 
on nursery stock with apparently satisfactory results. 
While I am on my feet, I wish to report the experiments which we 
conducted in Indiana in 1921 and 1922. We have been able to get just 
as good control in heavy sod as on bare ground, in the lightest sand 
soils and in the heaviest clay soils, and from the entire south and to the 
extreme north end of the state. Satisfactory results have been obtained 
both in our experimental plots and in a large number of commercial 
