CONTROL OF TOBACCO WILT IN THE FLUE-CURED DISTRICT. 13 



P2064T 



Fig. 2. — A field showing the results of continuous tobacco cropping, Creedmoor, N. C. 

 Tobacco was grown on this plat each year from 1911 to 1916, inclusive. Fully 80 

 per cent of the plants showed wilt on July 27, 1916. (Plat 1-B.) 



negligible. The effectiveness of grass and clover and of corn in 

 reducing the injury from wilt is shown in figures 3 and 4, re- 

 spectively. It should be noted, however, that the tobacco made 

 a much better growth after grass and clover than after corn. 

 On plat C, one portion of which had been cropped to peanuts 

 and the other to tomatoes, 58 per cent of the plants were af- 

 fected. The portion of the plat on which tomatoes had been grown 

 showed about 20 per cent more wilt than the portion cropped to 

 peanuts. Figure 5 clearly shows the marked injury from wilt 

 on this plat. The tobacco was mature and ready for harvesting 

 by July 27, and on that date there was only 5 per cent of wilt on 

 plat B, which had been cropped to sweet potatoes continuously for 

 five years. The tobacco was allowed to stand, however, and on 

 August 10 symptoms of wilt were shown by 21 per cent of the plants, 

 while no such marked increase occurred in the other plats. A simi- 

 lar condition was noted on plat 1-B in 1915, for on August 3 there 

 was only 3 per cent of wilt, while on August 11 there was 23 per 

 cent. The normal, gradual progress of the wilt in a tobacco field 

 is shown in Table IV, which gives the counts on the plats made from 

 June 29 to August 10, 1916. No wilted plants were observed a week 

 prior to June 29. 





