TOBACCO INSECTS AND DISEASES 497 



the production of seed and to increase the size and substance 

 of the leaves. Considerable judgment is required in this 

 work, for on it depends in large measure the uniformity 

 and yield of the crop. Slow-growing plants or those on poor 

 soil are usually allowed to develop fewer leaves than those on 

 rich soil or which are making rapid growth. Soon after the 

 top is removed, suckers will be produced from the axils of 

 the leaves. These should be removed when they reach a 

 length of about 3 inches. It is necessary to go over the field 

 several times to remove these suckers, since they continue 

 to appear as long as the plant is growing. If they are 

 allowed to develop, they will materially reduce the value 

 of the leaves on the main stalk, by depriving them of much 

 plant food. 



649. Insects and Diseases. Tobacco is not subject to 

 injury from any large number of insect pests or diseases. 

 The most frequent pest is the horn worm or tobacco worm, 

 which feeds on the leaves. This may be killed by applying 

 from J/2 to 1 pound of dry Paris green to the acre, mixing the 

 poison with about twenty times its bulk of flour and applying 

 it to the plants with a bellows. If too much poison is used, 

 it will burn the leaves. The smaller worms are killed by the 

 Paris green, but it does not affect the larger ones. These 

 must be removed by hand picking. Few diseases attack 

 the plant in the field. Damping off and other fungous pests 

 sometimes occur in the plant bed, but these are ordinarily 

 controlled by burning the bed before seeding, sowing only 

 the best seed, and giving proper attention to ventilation and 

 watering. 



650. Selection of Seed. A few of the choicest plants may 

 be allowed to produce seed. As a half-dozen will produce 

 enough seed for several acres, there is plenty of opportunity 

 for the selection of only the very best plants. These ought 



19 



