TOXIC GASES AS A COiSTTROL OF THE PEACH-TREE BORER. 23 



For 6 to 15 year old trees of average size, doses of 1 ounce 

 and of three-fourths of an ounce per tree have been found effective in 

 destroying the borers without injury to the trees. For very large 

 trees of advanced age, a somewhat increased dose may be desirable. 



As an added precaution against injury the base of the trees should 

 be uncovered 4 to 6 weeks after application, allowed to remain open 

 for a few days, and recovered. This precaution is especially neces- 

 sary if the application has been made very late. 



The use of p-dichlorobenzene in this way has been found to reduce 

 the infestation on the average from 6.77 to 0.41-0.36 larvae per tree, 

 approximately a 94 per cent control. 



WASHINGTON : GOVERXJIENT PRINTING OFFICE : 1919 



