16 METHODS OF CONTROLLING TOBACCO INSECTS. 



was cut. Professor Garman concludes that very little danger may 

 be apprehended from the arsenic left upon tobacco. In 1909 the 

 writer made several experiments to determine the amount of arsenic 

 left upon tobacco. To make the test severe, arsenate of lead was 

 used because this arsenical adheres to tobacco much longer than 

 does Paris green. August 13 the experimental plat received a spray- 

 ing at the rate of 5 pounds to the acre, and on August 18 a second 

 spraying at the rate of 4 pounds to the acre. Arsenate of lead in 

 dust form was used, hence the two dosages, amounting to 9 pounds, 

 were almost exactly equivalent in the amount of combined arsenic 

 to Professor Garman's dosage of 4£ pounds of Paris green. The 

 tobacco was cut September 8. The analysis, made by the Miscel- 

 laneous Division of the Bureau of Chemistry, showed an average of 

 0.347 grain arsenious oxide per pound. Heavier dosages of powdered 

 arsenate of lead left only 0.501 and 0.531 grain arsenious oxide per 

 pound. A fatal dose of arsenic for an adult is about two-thirds of a 

 grain, and this, of course, has to be taken into the stomach. Since 

 tobacco is not taken into the stomach, and since so little arsenic 

 will l)e taken into the mouth at anyone time, it is not believed that 

 there is the slightest danger in using tobacco that has been poisoned 

 with either Paris green or arsenate of lead; in fact, the writer is per- 

 sonally acquainted with tobacco growers who have been applying 

 Paris green to their tobacco for from six to eight years and who have 

 been chewing and smoking the cured tobacco without injurious 

 effects. 



POISONING THE TOBACCO MOTHS. 



The custom of poisoning " jimson" blooms with arsenide of 

 cobalt (flystone) to kill the tobacco moths when they feed has long 

 been recommended and has been practiced in nearly every tobacco 

 region, but unfortunately the custom has fallen into disuse. This 

 method of combating tobacco moths should be revived, for the kill- 

 ing of one female moth at " jimson" blooms will be equivalent to the 

 killing of several hundred worms later. 



The following is the formula for this poison: 



Arsenide of cobalt (flystone) ounce. . 1 



Water pint . . 1 



Sweeten, just before using, with molasses or honey. Place a few - 

 drops in each bloom late in the afternoon. 



SUMMARY. 



CUTWORMS. 



1. Plow sod land in the fall in preparing it for tobacco and keep 

 down all vegetation during the winter and spring. This will 

 starve the cutworms. 



