PESTS OF TOBACCO. 



235 



each tier of tobacco. Free ventilation in the roof is 

 absolutely essential to allow of the escape of warm, 

 moist air, any of the systems outlined in the chapter on 

 barns being available for this purpose. 



" White Vein" or "Stem Rot" appears in the latter 

 stages of curing cigar leaf, in the form of white, velvety 

 patches of long-piled mold, first affecting stalk and rib, 

 and later destroying the tissue near the veins and ribs 

 and causing the peculiar white veins. This disease is 

 also due to a fungus (Botrytis longibrachiata) that 

 thrives upon drying vegetation. "The fungus seldom 

 reaches maturity on the curing stalks," says Sturgis, 

 "for it requires some days and considerable moisture for 



FIG. 65. RED-LEGGED GRASSHOPPER (Pezotettix femur-rubrum). 

 Enlarged one-fourth. 



its complete development, hence by the time its vege- 

 tative threads are ready to produce the fruiting branches, 

 the stalks are too far dried to afford the requisite 

 nutriment. After the curing process is completed, how- 

 ever, the tobacco is taken down, and the stalks and 

 leaves most seriously affected with stem rot are 

 thrown down on the floor with the refuse which always 

 remains after the curing of a crop of tobacco. Here on 

 the damp, earth floors and in company with decaying 

 stalks and leaves, the stem rot fungus finds all the 

 conditions favorable to its further development. The 

 fungus spreads among the refuse, and produces its spores 

 in enormous quantities. It is not unusual upon enter- 



