TOBACCO 



545 



The wire-worm (Chambus caliginosellus) is injurious to to- 

 bacco plants in the Virginia tobacco fields. It is especially 

 abundant on fields which have recently grown up in weeds. The 

 means of reducing the amount of injury consists in preventing 

 the growth of weeds, especially of the Iron weed {Vernonia), in 

 fields where tobacco is soon to be grown. In case this weed is 



Fig. 222. — Sotjthekn Tobacco Worm. 

 u, adult moth ; b, full-grown larva ; o, pupa. 



present, it is recommended that instead of plowing it under it 

 should be mowed and burned. By setting tobacco very late, 

 this enemy is largely avoided, but the yield of tobacco is reduced. 



LABORATORY EXERCIS S 



In high schools located in regions where tobacco is not an 

 important crop, it will usually be advisable to omit this chapter. 

 The fact that the tobacco plant makes most of its growth 

 2n 



