218 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



proboscis, which somewhat resembles a horn and which may 

 account for the name of " hornblowers," commonly given them in 

 Maryland and Virginia. The pupal stage lasts about three weeks, 

 when the adults emerge, the whole life cycle requiring from six to 

 eight weeks. Usually two generations occur in a season through- 

 out most of the tobacco belt, but in the North there seems to be 

 but one generation, and in the Gulf States there may be three 

 generations. Occasionally the worms are overlooked in cutting 

 the tobacco and are carried into the barn, where they may do 

 considerable injury even after the tobacco is partially dry. 



Control. The most common method of control is hand-pick- 

 ing, usually termed "worming." In seasons when the worms are 

 not overabundant this may be the most practical method of con- 

 trol, but it is both tiresome and expensive, and the planter has no 

 means of predicting whether the worms will be more or less abun- 

 dant. Large flocks of turkeys driven through the fields will aid 

 most efficiently in this work. 



In many sections the worms are now controlled by spraying 

 or dusting with Paris green or arsenate of lead. More or less popu- 

 lar prejudice against the use of arsenicals has existed, as it was 

 thought the tobacco might be poisonous to the consumer. Careful 

 chemical examinations have shown, however, that the amount 

 left on the foliage after three sprayings would be far too small to 

 have any deleterious effect. The same prejudice formerly existed 

 against the use of arsenicals on potatoes, cabbage and other crops 

 but experience has shown it to be unwarranted. A real objection 

 to the use of Paris green is that it sometimes slightly burns the 

 foliage, so that arsenate of lead will doubtless be found preferable. 



Morgan* recommends dusting rather than spraying and con- 

 demns the use of Paris green. His summary of recommendations 

 is as follows: 



"Paris green, although an effective insecticide, frequently 

 burns tobacco very severely and may reduce the value of the crop 

 by as much as 50 per cent in exceptional cases. 



Arsenate of lead never seriously injures tobacco even under 

 the most unfavorable conditions. 



A dosage of Paris green large enough to be effective against horn- 

 worms can not be applied without grave danger of burning tobacco. 

 * Morgan, A. C. Farmer's Bulletin 867, U. S. Dept. of Agr. 



