The Birmingham age-herald., 1923-12-24
AIRPLANE WAR ON
 WEEV|LS SUCCESS
Calcium Arsenate Treatment Found To Be Most Effect
 i've Method Of Control

WASHINGTON. Dec. 23-Airplane attacks on the boil weevil, most de- structive enemy of the cotton crop. have proved successful and calcium arsenate dust has been found the most effective poison for the weevil and other cotton insects, the depart ment of agriculture announced to- day after extensive experiments.
 More tests are needed to develop better designs of planes and equip mert and to improve methods, and experimental work Is being continued as available funds permit. Calcium arsenate Is declared by the depart ment to be the best poison known at the present time for the weevil, but other poisons are being tested.
 B. R. Coad of the bureau of en- tomology, in charge of the cotton in sect Investigations at the govern ment station at Tallulah, La, dur ing the last few years has made ex- tensive tests of poisons and ways of applying them. It has been shown that dusting with calcium arsenate will make possible a profitable in crease in yield of seed cotton except where the land is low productive.
 Fields dusted with calcium arsen- ate by airplane this year showed an seed cotton over those on adjacent plantations that were not poisoned. Although the cost of dusting with airplanes, which were supplied and manned by air service of the army, is not definitely known, it is esti- mated to be about $5 per acre. At present prices of cotton, the gain from dusting was over $75 an acre. It Is thought the cost of dusting by airplane is less than with ground machines.
 The tests at Tallulah are designed to bring out information of many phases of the problem of cotton in section under control.
 Last summer the treatment cov- cred approximately 5000 on one plantation, the fields being unob- structed by buildings and trees and on the other broken up by woods, barns and cabins. On both of the plantations were heavily infested with the boil weevil and the cotton leaf worm. In addition to the air plane dusting. much cotton was treated with other poisons and with various machines and methods of treatment. Trials are being made in using the airplane in distributing poisons for the control of the other vii. the potato beetle and various or chard insects.
 The experimental work in apply ing calcium arsenate dusts by means of airplanes developed some import ant fundamental facts concerning the application of dust. When dust was first practiced it was found nee essary to work at night when the moisture on the plants would cause the dust particles to stick. Dust ap- piled by airplane in the daytime, was found to stick, and a pound of ma terial went much father than when applied by other means. Experiment. ha1i ba Ia gained because the particles of the powder are highly charged with pos itive electricity while the plants carry a negative charge. The charge of electricity is thought to be pro duced by the friction of the plane with the air and by the frictions of the dust particles with the air cur rent which has speed of 125 to 135 miles an hour. Scientists are now trying to produce this same sticking quality in dust applied by other ma chimes. Mir. Coad believes If all the particles could be separated a pound of calcium arsenate would be sutf1r cient to effectively cover an acre ot cotton. Ground machines are be- lieved equipped with high frequency and light voltage generators to de- termine If the dust can be charged in this way. The first suggestion of the charged dust explanation was ob-
  was precipitated when plane shed dust on it from above
 Development of airplanes espe- cially adapted to dusting may result ip better and more economical re- suits, it is said, and certain manu- factLrers of planes are taking an in- terest in the problem.
 Planes used last summer ' ere equipped with 420 horsepower Lb- erty motors but their design was such that only $50 pounds of cal cium arsenate could be carried, enough for only about three minutes of dusting. By using the same mo- tor and changing the design it Is thought it may be possible to carry ? 900 pounds at a load.
 The Gusting with calcium arsenate is effective not only in reducing the damage done by the boil weevil, bu' it also controls miscellaneous cotton insects including grasshoppers, cat erpillars and worms, but not lice and other sucking insects, and not the pink boil worm which works inside the boil.
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