404 STATE HORTICULTURAL SOCIETY. 



CELERY LEAP BLIGHT. 



As the leaf blight is dwarfing and injuring celery so much in many 

 localities and sjpreading to others, it was thought best to investigate this 

 disease and give it a portion of our consideration along with the celery 

 insects. In many places over the state the leaf blight is not known. In 

 fields where celery has been grown on the same ground for a series of 

 years, the blight through the hottest part of the season is severe. It is 

 very generally known among celery-growers in these places as " sun 

 blight" and is supposed to be produced by the hot sun. One season, 

 several years ago, it took nearly the whole celery crop at Kalamazoo. The 

 blight has troubled the fields in the northern peninsula for the past three 

 years, as Mr. Wheeler, our station botanist, learns through correspondence. 

 The same letter says, "'White Plume' and 'Golden Self Bleaching' 

 sufiPered more than other varieties. ' Henderson's New Rose ' has been 

 entirely free from blight." 



The blight is caused by a fungous disease working inside the celery 

 leaves. No experimental work has been done on it here. Dr. B. T. Gal- 

 loway has experimented on the blight in eastern fields and he kindly sends 

 his unpublished notes for our use. The following are his notes in full: 



CELEEY LEAF BLIGHT, AS AFFECTED BY WATER SUPPLY TO THE PLANT. 



Celery leaf blight, caused by Cercospora apii, is an exceedingly destructive disease, 

 especially in the eastern part of the United States. For several years we have been 

 making experiments in the hope that some means of cheaply preventing the trouble 

 might be discovered. In 1890, 1891, and 1892 a number of trials made were with various 

 fungicides, including both liquids and powders, but none of these gave very satisfactory 

 results. In every case where the celery was planted on upland soil it blighted badly, 

 despite the fact that the leaves were kept nearly covered with such well-known fungi- 

 cides as Bordeaux mixture, ammoniacal solution of copper carbonate, etc. Where 

 these preparations were used, however, the celery was not so badly attacked by leaf 

 blight as the plants receiving no treatment at all. 



Noticing that celery on low, moist ground was seldom severely injured by blight, an 

 experiment was made in 1892 on upland soil to test the effect on the disease of water 

 applied to the roots. The plants selected for the experiment were fully exposed to the 

 sun and were set in such a way that they could be flooded sufficiently often to keep the 

 ground always soaked. Without any further treatment these plants made a vigorous 

 growth and were almost wholly free from blight. The average height of the plants when 

 bleached was thirty-two inches. Plants in the same bed which received only water fall- 

 ing naturally, as rain, blighted very badly, in consequence of which there was not enough 

 leaves to bleach when the time came for this operation. In height these plants aver- 

 aged a little over eight inches, or about one fourth that of the watered celery. The 

 experiment shows the importance of an abundant water supply for this crop and 

 explains in a measure why in certain localities celery is seldom affected with the 

 disease. Of course it may not be practicable for all upland celery -growers to water as 

 extensively as seems necessary to keep the crop growing and free from disease, still 

 there are no doubt many places where irrigation could be practiced at comparatively 

 little expense, making the crop, even in regions where the soil and climate is naturally 

 unfavorable, a certain and profitable one. 



G. C. DAVIS. 



