BULLETIE^ ISTo. 213. 



DEPARTMENT OF BOTANY. 



TOBACCO WILDFIRE IN 1922.^ 



BY P. J. ANDERSON AND G. H. CHAPMAN, 



INTRODUCTION. 



Wildfire in the Connecticut Valley. 



Wildfire continues to be the most serious menace to the tobacco-grow- 

 ing industry of the Connecticut Valley. The season of 1922 was not less 

 disastrous than that of 1921. 



Beginning with the first recorded infection on May 7, fresh reports of 

 infected seed-beds came in from every side with increasing frequency until 

 it was estimated that 30 per cent of the beds of the valley contained 

 some wildfire. No tobacco-growing town in Connecticut or Massachu- 

 setts escaped. Continuous rains and cloudy weather during the seed-bed 

 period furnished ideal conditions for the spread of the disease and at the 

 same time made it difficult to apply remedial measures. The same weather 

 conditions continued throughout the setting period of June, and it was not 

 surprising that the disease appeared in the fields almost as soon as the 

 plants were established. It continued to spread there until, by the 4th of 

 July, wildfire was raging in half the fields of the valley. The Broadleaf 

 section was much more seriously affected than in 1921, while, on the other 

 hand, many of the growers of other varieties escaped with less trouble than 

 during the previous year. Growers were discouraged both by the wild- 

 fire and by the poor growth of the tobacco during this unfavorable weather, 

 and some of them even plowed up their fields. But after the first week in 

 July the weather cleared, there were no more long-continued rains, and 

 such rains as occurred were followed by hot, clear weather. During the 

 next three or four weeks wildfire spread hardly at all and the tobacco 

 grew rapidly, covering the diseased leaves with healthy ones until many 

 growers felt that the disease had passed. Rainstorms, however, became 

 more frequent during the last few da.ys of July and were accompanied by 

 increased spread of disease throughout the topping period and, with but 



1 a report of co-operative work carried on by the Massachusetts Agricultural Experiment 

 Station and the Tobacco Experiment Station of the Connecticut Agricultural Experiment Sta- 

 tion. Published, with a different introduction, as Bulletin 2 of the latter station. 



