214 Bulletin 132. 



trimmings, and as thep^antsaresubsequently thoroughly washed, 

 it seems that this efficient fungicide might be used without 

 encountering the enmity of the most fastidious purchaser. 



As previously mentioned, it is not known how the fungus 

 causing this disease passes the winter, but it is quite likely that 

 all diseased leaves and culls, both from the field and root house, 

 are certain sources of contamination another year. It is doubtless 

 impossible to destroy all such diseased material, but the more that 

 is destroyed the less the probability of abundant reappearance ; 

 and if the disease is to be fought effectively, it must be fought in 

 every stage. 



Special Characters of the Fungus, and Artificial Cultures. 



According to Halsted* the first mention of a Scptoria on celery is by 

 Briosi and Cavara f, in 1890. Here the fungus is given under the name men- 

 tioned above {Septoria Petroselini Desm. , Var. Apii B. & C. ) %• By Halsted, 

 Chester, and Ellis this fungus has been compared with the species distributed 

 by Briosi and Cavara, and they see no reason why our American form is not 

 the same. There seems to be some doubt regarding the character of the 

 spores. Halsted figures them uniformly septate, while Chester apparently 

 saw no septa, and he describes them as ' ' apparently non-septate, or septu- 

 late, guttulate." I have carefully examined a number of specimens from 

 the field and from artificial cultures. Invariably mature spores are septate ; 

 but often the septa are not visible vrithout the use of stains. 



The spores germinate readily in agar, so that isolation cultures may be 

 made in petri dishes. From such cultures, transff -^s to tubes of sterile bean 

 stems have given good growths of the organism it, a pure form. These cul- 

 tures have gi-^en mature pycnidia in a few weeks. The perithecia are then 

 formed superficially upon the bean stems, and formed of loosely woven, 

 brown hyphae. Humphrey § has suggested that the Septoria is connected 

 with the Cercospora as pleomorphic forms of the same species. His sugges- 

 tions, I believe, are based mainly upon gradations in spot characters. Chester 

 was never able to find both fungi in the same spot, although both were some- 

 times found upon the same leaf. My cultures indicate as clearly as possible 

 thus far that these two fungi have no genetic connection, if we may judge at 

 all from growth characters. Under similar conditions, not only has the 



♦Report, New Jersey Ag'l. Exp. Sta., 1891, p. 256. 



t Funghi Parasitti Fascecola, VI . No. 144. 



\ Note. The only additional foreign mention yet encountered of a celery disease due to 

 a Septoria is a short article by Sorauer on " Die Fleckenkrankheit des Sellerie," in 

 Zeitschrift fiir Pflanzenkrankheiten, VI. (1896), H. 3, p. 191. The spores of this Septoria 

 ■ jre described as non-vacuolate, non-septate. 



§ Report Mass. Agl. Exp. Sta., 1891, p. 231. 



