6 



METHODS OF CONTROLLING TOBACCO INSECTS. 



crop lias to be set late than would be the case if the beds were pro- 

 tected. The grower should always be prepared to fight the flea- 

 beetle, for often prompt attention to insect attack upon the plant 

 bed will enable him to save his bed and thus be prepared to set all 

 his crop early. 



An early-set crop of tobacco has two very important advantages 

 over a late-set crop. The first is the production of a better grade 

 and of more pounds to the acre, as mentioned above. The second 

 advantage is often more important than the first. An early-set crop 

 will frequently mature in time to be cut before the August "shower" 

 of tobacco worms is large enough to do it serious injury. This point 



will be explained more fully in the fol- 

 lowing discussion of the tobacco horn- 

 worms. 



THE TOBACCO HORNWORMS. 



(Phlegethontius sexta Joh. and Phlegethontiiis 

 quinqnemaculata Haw.) 



In the "dark tobacco" districts of 

 Kentucky and Tennessee the horn- 

 worms are the most injurious tobacco 

 insects, and they are important enemies 

 of this crop in every district in the 

 United States where it is grown. There 

 are two species, the northern tobacco 

 worm (Phlegdliontius quinquemaculata 

 Haw.) and the southern tobacco worm 

 (Phlegethontius sexta Joh.) (fig. 7). The 

 northern tobacco worm is called also the ' ' Spanish worm" in Tennessee 

 and Kentucky. This "worm," or larva, is in general darker than the 

 southern tobacco worm, but the easiest way of distinguishing the 

 two species is by the white markings on the sides of the body. The 

 northern worm has 8 V-shaped markings on each side of the body, 

 each of which incloses a spiracle, or breathing pore. The southern 

 worm, has 7 oblique lines on each side of the body, each of which 

 passes in front of a spiracle. 



DISTRIBUTION. 



In general, as the common names indicate, the northern worm 

 is most numerous in the north and the southern worm is most 

 numerous in the south. The northern species is found as far south as 

 Florida, though it is rare, and the southern species has been collected 

 in Canada. At Washington, D. C, on the authority of Dr. F. H. 

 Chittenden, the northern species predominates, while in Tennessee 



Fig. fi.— Knapsack spray pump. 



