Airplane Spraying 



Airplane spraying is ordinarily a custom arrangennent with firms 

 doing this work. The method offers advantages of speed and convenience 

 for growers who have large fruit plantings. Thousands of acres of apples 

 and pears are given preharvest spray fronn the air annually in the exten- 

 sive fruit-growing centers of the Northwest. 



For airplane spraying the only practical stop-drop chemical is NAA. 

 Any drift from airplane applications of 2,4,5-T or Z, 4, 5-TP that might 

 reach pear trees could damage foliage and fruit. 



NAA sprayed on apples and pears by plane is prepared in concentrated 

 form. The same quantity of material that would be dissolved in 1,200 

 gallons of water for ground spray is put into 5 gallons of oil emulsion for 

 plane spraying. When the spray is diffused by air-blast, the air carries 

 the spray in fine mist to the trees. 



FURTHER RESEARCH ADVANCEMENT 



Continued research with stop-drop chemicals applied to apples and 

 pears is aimed chiefly at 2 major goals: 



1. To find more effective compounds . . . serving many varieties, 

 possibly with greater economy and convenience. 



2. To understand more accurately the physiological processes involved 

 and to learn whether it is possible to predict biological effects of different 

 growth regulators from their chemical structure. 



Agriculture - Washington 



