Characteristics and use of special materials. Chemicals in granular and fumigant 
form are increasing widely inuse butlittle basic research has been done on the mechanics 
of application of these materials. More accurate metering equipment is needed for granular 
pesticides. Methods should be developed to determine whether granular material will 
break up during a particular metering or application process, 
We also need more accurate metering and application equipment for fumigant 
chemicals than are available at the present time. The effect of soil nonhomogeneity 
upon pesticide action throughout the soil needs considerably more research, as well 
as methods of sealing soil pesticides in the soil. 
FUTURE PROBLEMS 
Basic Research. Much progress has been made in pesticide application by following 
the more obvious ways and means of applying pesticides. Noapologies should be made 
for this procedure since the applicability of the results and the benefit to agriculture 
to date have undoubtedly been highest with this procedure. However, as with other 
progress, the easier gains have been made and there is urgent need for expanded 
basic engineering research on the physical forces (gravitational, inertial, thermal, 
electrical, and viscous) which control the deposition of pesticides. The need then is 
for basic research to define the fundamental physics of aerosol behavior. 
Applied Research. Continuous research will be necessary to develop machines and 
techniques for more accurately directing and uniformly applying all types of pesticides, 
liquid, dust, and granular, to all important crops. 
As entomologists define insect pathogens which are harmful to insects but not to 
higher animals and plants, equipment will be requiredto properly dispense and distribute 
these materials. For example, research reports indicate that virus of the tent caterpillar 
can be concentrated so that a solution of material weighing 1 pound will furnish control 
when spread evenly over 50 acres of trees. Such an application problem challenges the 
imagination. 
Aerial applications, including those by helicopters, will continue to advance with 
increasing knowledge of the requirements. 
In conclusion, we wish to restate our firm conviction that greatest progress will 
come with a well coordinated and inte grated effort, including those of the engineer and 
the biological scientist. 
SELECTED REFERENCES 
(1) Brazee, Ross D., and Wesley F. Buchele. Electrostatic Precipitation of Agricultural 
Dusts, An Outline of Research and Literature, U.S. Agr. Res. Service ARS-42-29, 
(July 1959), (Contains a summary of publications relatedtoelectrostatic precipitation 
of dusts) 
(2) DeJuhasz, K. J. Spray Literature Abstracts. Am. Soc. Mech. Engineers (1959). 
(Abstracts of about 1300 literature items on sprays, atomization, aerosol mechan- 
ics, and nozzles. Includes experimental and measuring methods and instruments, 
theories, and application). 
(3) Fuks, N. A. The Mechanics of Aerosols. Translated by M.S.P.E. Lachowicz. U. S. 
Dept. of Commerce, Office of Technical Services Translation 59-21069 (1959) 
(A comprehensive monograph of aerosol mechanics, presenting work from 580 
references. Emphasis on smaller aerosols, usually D<<100 microns.) 
83 
