14a EXPERIMENT STATION. [Jan. 



Dr. Chapman's tobacco investigations have gone forward in 

 a satisfactory manner. A report of this work up to the season 

 of 1919 has been prepared and presented for publication as a 

 bulletin. 



In Mr. Clark's study of optimum light requirements of 

 plants, important data have accumulated. In the field com- 

 parative studies were continued on yield, size and reproduction 

 under different light intensities provided by the tents mentioned 

 in our last annual report. In the laboratory further studies 

 were made on the reaction between chlorophyll content of 

 leaves and the light intensity under which they developed. 



Weather conditions during the growing season of 1919 fa- 

 vored the development of many plant diseases, and the early 

 season conditions were such as to retard and injure vegetation. 

 Low temperatures, accompanied by high winds late in April, 

 were fatal to peach blossoms which had blown, but few un- 

 opened buds were injured. The percentage of injury was so 

 small that material reduction of the crop did not result. 

 Japanese plums suffered more severely than peaches. Other 

 fruits did not sustain noticeable injury. An abnormally wet 

 May was responsible for much loss to vegetable garden crops, 

 especially from stem and root rots caused by certain soil 

 fungi, Fusarium stem rot of peas was prevalent throughout 

 the State, and the crop was greatly reduced by it. Instances 

 of total loss were not uncommon. Similar diseases of beans, 

 caused by a Fusarium and Rhizoctonia, were equally destruc- 

 tive. Potatoes suffered severely from rotting oft* of the young 

 sprouts by Rhizoctonia. 



Throughout the summer instances of dying back of shrubs 

 and trees came to our attention. This condition was not 

 confined to any particular period, but its initial outward 

 appearance occurred on dift'erent plants from the time leaf 

 buds began to open until the close of the season. In the 

 majority of cases no fungous or other parasites were present. 

 After careful study of the situation it became apparent that 

 the trouble could be traced back to moderate injury from the 

 severe winter conditions of 1917-18. As pointed out in our 

 last annual report, many trees and shrubs thus injured, but 

 not killed outright, were unable to recuperate, owing to the 



