224 MISC. PUBLICATION 273, U.S. DEPT. OF AGRICULTURE 



Figure 103. — With a long hose it is possible to reach distances of 1,500 to 

 5,000 feet from the spray pump. 



With the development of DDT new progress in airplane spray- 

 ing for control of forest defoliators became possible, for this 

 insecticide has many characteristics that make it ideally suited 

 to this work. Incredibly small amounts — from % to 1 pound per 

 acre — are sufficient for effective control. DDT can be dissolved 

 in fuel oil, which flows freely and uniformly from spray jets 

 without clogging. Small quantities — 1 gallon of spray per acre — 

 are sufficient to give residual deposits that are lethal to crawling 

 insects for many weeks. If dosages have been kept below 1 pound 

 per acre, no deleterious effects on birds, fish, and other wildlife 

 have been evident. 



