-9- 



5. The use of air dusting may not save labor; on the other hand, it might 

 actually discourage the hiring of year-round help and therefore other 

 desirable orchard operations, such as pruning, might not be accomplished for 

 lack of year-round workers, 



6. The coverage of low branches in thick orchards may be poor and where these 

 conditions prevail increased application rates per acre should be considered. 



7. Insect control may be difficult, especially where heavy populations of codling 

 moth, mites or red-banded leaf rollers are present. In some instances, the 

 use of more specific materials in spray form might well be considered. 



8. A lot of grower cooperation is necessary to make possible efficient schedul- 

 ing and, above all, to avoid waste of airplane and pilot time especially if 

 the grower help does not keep the dust supply to the plane loading point on 

 a punctual basis. 



9. Drift of dusts is a problem. It will be necessary to coordinate with neighbors 

 to prevent any possible chance of injury to humans or livestock. Remember 

 that all spray or dust residues are extremely poisonous to those who do not 

 know enough about them. 



10. Noise, especially in thickly populated areas, may be a problem. 



The kinds of aircraft most suitable for orcliArd vjork conntltute a controversy. 

 The three most cofomoniy used kinds or types have been used in our work, each with 

 success. The Cubs are less expensive than any, if purchased new, but they do not 

 seem to be suited to our conditions partly because they cannot carry a very heavy 

 load. The second type used is the helicopter. It is ideal in that it can land 

 almost in any clearing. It may be safer to operate and can cover smaller acreages 

 faster. On the other hand, it is very expensive to buy and to operate and apparent- 

 ly requires an extremely high degree of pilot proficiency to operate. Like the 

 Cubs they cannot carry very heavy loads. The third tyj 3 we have used is the bi- 

 plane which is almost always of the war surplus PT-17 or Stearman make. To begin 

 with, these are available to operators at only a fraction of their original cost. 

 The Stearman seems to be the "Model A" of planes being easy to operate, easily 

 serviced, reliable and inexpensive to operate. It can carry a load of 800-1,000 

 pounds using a 250 horsepovjer engine which is very important. 



We have not found a significant difference in scab or insect control between 

 the various types of aircraft. The use of effective materials, carefully timed 

 application, flying ability of operating personnel and dependability of equipment 

 are believed to be far more important then the kind of plane used. 



Space will not permit a detailed discussion of why air spraying has not been 

 a practice in our orchard program instead of dusting. In the first place a high 

 concentrate, low gallonage cuxture - down to less than 5 gallons per acre - would 

 be necessary in order to gain an advantage from a load weight standpoint. Wettable 

 powders cannot be used at such high concentrations, and the only available solvents 

 seem to be toxic to apples. Sprays would be more favorable from a drift and deposit 

 standpoint than dusts. Vermont growers have applied TEPP at 16X by plane, some urea 

 at 5 gallons per acre, and thousands of acres of orchards have been treated with 

 hormones in liquid form for fruit drop control at harvest time. 



