PESTS OF TOBACCO. 249 



other weeds as well as upon the tobacco plant, but its 

 injuries do not seem to be so decided as the first named. 

 These bugs make very small holes in the leaf, but the 

 damage resulting from them is inconsiderable. 



The Tobacco Miner is a new pest that attacked to- 

 bacco for the first time in 1896, being noticed in three 

 townships in one county in North Carolina. The cater- 

 pillar is about half an inch long, and greenish, with 

 a dark brown head. It makes an irregular or blotch 

 mine by eating the green matter between the two sides 

 of the leaf, leaving the skins intact and the leaf trans- 

 parent. The caterpillar is extremely voracious and as 

 several usually mine one leaf, the leaf is soon rendered 

 worthless, and it is feared that the pest may be widely 

 prevalent. It has been carefully studied by Gerald 

 McCarthy, botanist North Carolina experiment station, 

 and the facts and illustrations (Fig. 66) are from its 

 bulletin 133. 



The insect is a native whose common food plant has 

 been the perennial weed, Solatium Carolinense, com- 

 monly called horse or bull nettle. This weed is rather 

 common on dry, sandy soil from Connecticut southward 

 along the coast to Florida, and westward to the Missis- 

 sippi. The range of the insect is co-extensive with its 

 host plant, and includes nearly the entire tobacco-grow- 

 ing area of the United States. It is well known to 

 economic entomologists that the natural increase of any 

 insect is chiefly regulated by the abundance of its food 

 plants. Insects which subsist upon a few species of 

 weeds of waste ground must necessarily lead a very 

 precarious existence, and do well if they hold their num- 

 ber from year to year. When such an insect changes 

 its wild food plant for a cultivated species, the rela- 

 tively almost infinite abundance of the latter causes a 

 parallel increase o the insect, which, soon overflowing 

 its natural boundaries, or the range it occupied before, 



