1919.] PUBLIC DOCUMENT — No. 31. 21a 



bodying the results of this work should be ready for early 

 publication. 



Mr. Clark's study of light in relation to plant growth was 

 again carried to the field last summer, with striking results. 

 The unique tents which provide varying light intensities for 

 the growing crops which they screen have proven very satis- 

 factory for this work. Laboratory studies in connection with 

 this project have continued. 



At the suggestion of Dr. Neil E. Stevens of the Bureau of 

 Plant Industry, United States Department of Agriculture, 

 certain physiological studies in connection with the problem of 

 controlling decay of ripe strawberries were undertaken last 

 summer. A large amount of laboratory work has been done by 

 Mr. Clark, and this will be continued next season. 



The work under the general project for investigation of so- 

 called tobacco sick soils, in charge of Dr. Chapman, has pro- 

 ceeded in accordance with plans previously outlined. Impor- 

 tant results have been obtained both in the laboratory and in 

 the field. This work is becoming increasingly valuable to the 

 tobacco growers, and they, in turn, have shown their apprecia- 

 tion of it. In connection with this project a study of meteoro- 

 logical factors in relation to the tobacco crop has been made, 

 and the data gathered are practically ready for publication. 



Experimental spraying of celery for the control of early and 

 late blights, conducted by Mr. Krout, has continued through 

 two seasons. This work has been done on plots laid out as 

 parts of commercial fields in the eastern part of the State and 

 at the market-garden field station. Data already obtained 

 indicate that an efficient method of control is at hand. Another 

 season's work on this project should provide sufficient results on 

 which to base definite conclusions and recommendations which 

 can be adopted by growers. 



The project for investigation of onion diseases is referred to 

 elsewhere in this report. 



The growing season of 1918 was preceded by a winter notable 

 for its severity. Periods of extreme cold caused unprecedented 

 winter injury and killing of trees and shrubs. Scarcely any 

 species escaped entirely, and some native species of trees which 

 have remained hardy through previous winters were killed 



