MICHIGAN ACADEMY OF SCIENCE. 127 



"blancliiug of the leaves Avliich accompanies tlie stunting. A num- 

 ber of such plants in a row makes a conspicuous spot in a field. 

 These spots gradually enlarge year after year. Spots containing 

 many hundred square feet have been found in some fields. In one 

 or two cases dirt fr<»m such areas had bt'eu used for seed-bed p\ir- 

 poses. As a result an area larger than an acre became completely 

 infected and crops failed year after year. 



The finding of the disease in certain fields following flood- 

 ing and washing of soil froui diseased area seems to indicate the 

 transference of infectious material in this way. The common 

 source of infection however is from diseased seedlings and the 

 appearance of small diseased areas sprinkled all over a field has 

 been traced to a seed bed where a small percentage of the plants 

 showed the disease. The restriction of the disease to these types 

 of transference seems required b}- the observation made so far. The 

 failure to find evidence of spread of the disease by the ordinary 

 methods of cultivation or by mere walking from the diseased areas 

 to healthy ones is a marked peculiarity which is not as yet ex- 

 l)lainable. 



The disease produces loss only in the early, self-blanching varie- 

 ties. Although the disease is found in the winter or green varieties, 

 a successful crop of these may be grown on land where other varie- 

 ties are a failure. 



The causal bacterial organism has been isolated and its patho- 

 genicity tested. Control measures consisting of soil sterilization 

 by steaming have been successfully tried. The details of this work 

 are reserved for future i)ublication. 



Tlie disease is a serious menace to the celery industry about 

 Kalamazoo. Many areas of this extremely valuable land are now 

 not fit for growing the high-priced product, although other crops 

 may be safely ])]anted. A survey of the region showed spots in the 

 majority of fit-lds in one large marsh. 



For this disease which as yet lacks a common name. I pro- 

 pose the name, tlie Stunting Disease of Celery. 



THe ^clerntiuia Disensr. Tn the fall of 10] 4. specimens of winter 

 celery were sent to the laboratory in a badly rotted condition. 

 These i>lants had rotted in the Ircnclies Avhere they had been cov- 

 ered with dirt in the usual manner for keei)ing celery for the winter 

 market. In many areas in the trenches all the celery was decayed. 

 The docayed celery Avhen first sent to the laboratory showed a white 

 felt of hyphae. After al)out a week in tlie laboratory, characteristic 

 black sclerotia appeared in great abundance niton the rotted jtlaiits. 



