300 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 13 
decided to advise dusting with dry powdered arsenate of lead one 
pound to eight pounds of dust lime, or liquid spraying with one pound 
to 25 gallons water, using machines in either case, or if necessary 
applying the dust by hand. This advice was sent to all county 
agents, and to the press through the extension service. We then set to 
work to prove the efficiency and safety, or otherwise, of this advice. 
Among the tests was one in which a plant was dusted lightly by 
hand with the one to eight mixture, paying no special attention to the 
lower sides of the leaves; the plant was caged and ten nearly grown 
larvae were placed on it. This cage was started by the writer at 6:30 
a. m. August 8, the cage being carefully “floored’’ with white paper to 
facilitate finding any larvae which might drop. By the 12th (in four 
days) seven of the larvae had died; by 8:30 a. m. August 14 (in six days) 
eight had died with all the symptoms of poisoning, one had died of 
bacterial disease, while the remaining one had pupated; it emerged as a 
moth, female, on August 22. This indicated a killing efficiency of 
80 per cent in hand applications. Mr. Leiby at Terra Ceia secured 
similar results in cage work. Such explicit data could not have been 
established in field tests because many worms were already leaving the 
plants to pupate. The remedy was effective. 
On August 8 a vigorous row 112 feet long was dusted by hand as 
would be done in field practice for potato beetles. Observed for over 
a month it showed no injury in comparison with an untreated row 
alongside. The remedy was safe. 
Another row was treated very heavily, using several times more 
than could reasonably be needed,—the injury was slight and tem¬ 
porary, the row was soon as good as its check. The remedy was vir¬ 
tually fool-proof. 
We also tested it at strength of one pound to four pounds lime; 
one pound to two pounds lime; one pound to one pound lime; and pure 
arsenate alone, all these being applied by hand. All of these greater 
strengths gave injury, more severe as the proportion of arsenate 
increased. 
Similar tests with dusting machines showed that with these the 
greater strengths could be safely used, but were not necessary. A very 
careful farmer whose field was under observation tried arsenate alone 
successfully as a test on his own account, but the application was very 
light. That same farmer afterwards said that the arsenate remedy 
was so simple, so effective, and so practical that had he appreciated it 
at its full worth two weeks earlier he would be five thousand dollars 
better off—as it was he prevented much of the loss,—he considered 
the clover worm on soy beans as a solved problem. Other testimony 
to like effect could be quoted. The remedy was practicable, it was not 
prohibitive either in cost nor labor of application. 
