14 Farmers’ Bulletin 1246. 
DANGER OF INJURING TREES. 
Most materidls effective in killing insects will also injure trees 
when used in large dosages. In the successful use of insecticides 
it is necessary to ascertain the minimum amount which will kill the 
insect and which will not injure the plants treated. Para-dichloro- 
benzene is a good example of such a chemical where the margin of 
safety is adequate for its practical employment as an insecticide, but 
where care on the part of users must always be employed. Close 
adherence to the directions given, as to the time, method of applica- 
tion, and dosage, is urged upon the users of the ‘‘paradichlor”’ 
method of peach-borer control. In the experiments of the Bureau 
of Entomology when so used, no injury has been noted to trees 6 
years of age and over, and its use on trees younger than this is not 
recommended. 
