-135- 
oil at the rate of 2 quarts per aore. Exoellent control of adult Aedes 
taeniorhynchus in densely wooded areas was obtained by this means. 
Sucoess was also attained in 1943 by the use of a 20-percent DDT solu- 
tion from exhaust equipment installed on a Cub plane* A* W. Lindquist 
aided in additional tests conducted by the Army in the Panama Canal 
Zone in April, 1944, and demonstrated a 98 to 100 percent oontrol of 
Anopheles alb Im ams Wied., and Mansonia fasoiolata L. Arr., "rtien 2 
quarts of a 10-percent DDT solution were applied by a Eusman-Longcoy 
spray unit installed on a Piper Cub plane* Some details of operational 
planning for the application of Wtt residual spray to the interiors of 
375,000 houses in 110 endemio malarious counties of 13 southern States 
this year have been presented. Procedures followed and formula, ma- 
terial, and equipment being used in current operations are preliminary 
and subject to further refinement and basic alteration as a result of 
experience gained from routine project operation and field experimental 
work. The concentrate solution, whioh is carried by the hand sprayer 
crew in an Army-type 5-gallon gasoline can, is composed of 35 percent 
DDT in xylene, plus a small quantity of emulsifier. This solution is 
readily miscible in water. The emulsion has a breaking time of 30 
minutes but this does not occur while the sprayer is agitated as in 
normal usage. Other comparative advantages of an aqueous emulsion are 
freedom from fire hazard and reduced solvent action and spotting on 
interior finishes, clothing, and other fabrics. An emulsion applica- 
tion rate of 4 ml. per square foot will be used. "While lower quanti- 
ties can be applied on experimental activities, experience indicates 
that most laborers apply at least 4 ml. per square foot to obtain 
visible wetting of the surface. Under these conditions, a DDT applica- 
tion rate of 100 mg» per square foot dictates the selection of a 2^- 
percent emulsion strength.— Henderson (206) . 
DDT insecticides are so muph more effective than previous weapons 
against malaria mosquitoes that for the first time iiiere is a practical 
hope for eradicating that disease from this country • 
"For the control of mosquito larvae DDT as a dust is no more use- 
ful than paris green. At present, with a price differential of well 
over 50 cents a pound, it would seem inadvisable even to experiment 
with DDT as a dust larvioide. The chief value of the spray is that 
extremely small quantities may be as effective as the application of 
large amounts of fuel oil. A 5 percent dilution in kerosene or diesel 
oil is excellent. The ideal treatment recommended for this dilution 
is 1 to 2 quarts per acre, as contrasted with 18 to 20 gallons of fuel- 
oil dispersal. These figures give some idea of the minute quantity 
that should be used." 
