234 TOBACCO LEAF. 



It appears from his work, as well as from the experience 

 of practical growers, that a crop is very seldom cured at 

 the North without showing some traces of disease. 

 Even during the most favorable seasons, the disease 

 makes its appearance in the center of the curing barn, 

 where the temperature is higher, and the moisture more 

 retained in and about the leaves, whereas, in unfavorable 

 seasons, the loss often amounts to practically the entire 

 crop. Nor is it confined to the seedleaf sections, being 

 common in the heavy shipping and yellow districts. It 

 is not the mold (Cladisporium) that does the mischief 

 so much as the bacteria, which cause the rapid decay. 

 Sturgis found that warmth as well as moisture is con- 

 ducive to pole burn, and this fact emphasizes the neces- 

 sity of securing good circulation of air in the curing 

 barn, and especially when artificial heat is employed. 

 All attempts to inoculate thoroughly cured tobacco with 

 bacteria of pole burn were failures. Sturgis regards 

 this as partial confirmation of the generally expressed 

 view, that when tobacco has cured to a certain degree, 

 the period varying from ten days to three weeks after 

 hanging, there is very little danger of pole burn. 



The remedy for pole burn has already been de- 

 scribed in the chapter on curing. It is to get rid of the 

 excess of warmth and moisture, which can only be done 

 by a complete system of ventilation. For this purpose, 

 Sturgis strongly endorses horizontal ventilators near the 

 ground, a similar row for each tier of tobacco and one 

 or more large ventilators along the ridgepole. The ven- 

 tilators in the walls should open horizontally at inter- 

 vals of about four feet, as shown in Fig. 59. They 

 should be from five to ten feet long, one foot high, hung 

 from the upper edge by strap hinges, so as to be raised 

 and hooked up, and occupying the full length of the 

 building. When these are all open, the air will enter 

 freely, not only near the ground, but also just below 



