November IS, 1910] 



SCIENCE 



727 



preliminary attack of seedlings, no leaf 

 change takes place. Finally, however, as the 

 lesions become confluent and a collar rot is 

 being effected the margins of the outer leaves 

 take on a reddish tinge; this latter symptom 

 is usually followed by wilt and a quick col- 

 lapse. 



It is in half to two thirds grown plants 

 that the disease is seen at its worst. Here it 

 causes a rapid destruction of the cambium at 

 a level with the ground, which extends 

 quickly above and below. The fungus pene- 

 trates the xylem, followed by bacterial decay. 

 The severely affected plants show a metallic 

 bluish-red color on the margins of the outer 

 leaves, with also some evidence of wilt. 



The rot lesions extend deeply into the stem. 

 As soon as a collar rot is effected the plant 

 collapses with a sudden wilt. Soon the stem 

 becomes so badly rotted that the wind often 

 upsets the plant by breaking its connection 

 with the root, and the plant blows away. 



Even in the advanced stages of the disease 

 the fruiting bodies of the parasite may be 

 found at the margins of the lesions. 



The losses in the Clyde and Fremont dis- 

 tricts have been excessive. In the vicinity of 

 Clyde it has been working in conjunction 

 with the Fusarium wilt, the two diseases hav- 

 ing almost driven the cabbage growers out of 

 the business. Several cases were noted by 

 growers where their fields last year suffered 

 almost total loss from this disease. In a field 

 at Fremont put to cabbage both last year and 

 this, the amount of Phoma infected plants 

 was fully 65 per cent, on date of August 4, 

 this season. 



The progress of cabbage diseases at Fre- 

 mont, which is a comparatively new cabbage 

 district, shows the Phoma wilt is much more 

 aggressive at present than the Fusarium wilt, 

 though the latter has appeared in a very lim- 

 ited amount in two fields. 



During the season the disease has been re- 

 ported with specimens from several other lo- 

 calities in the state. From a statement made 

 by F. L. Washburn, state entomologist, in his 

 1906 report (p. 18) to the governor of Min- 

 nesota, it is quite probable that the disease 



appears there. He notes in reviewing the 

 club root of cabbage, " Many market garden- 

 ers confound the work of the maggot with 

 diseases which affect the root and have no 

 connection whatever with the maggot. This 

 is noticeably true of a form of rot which 

 sometimes affects the roots, causing wilting 

 and death of the plant." 



That cabbage maggots, the cabbage cur- 

 culio and wireworms are active in furthering 

 the disease, is noted by Bos and Quanjer (see 

 both citations above). The latter has shown 

 that Phoma oleracea Sacc, which heretofore 

 has been regarded as a saprophyte, is directly 

 pathogenic on fully grown and harvested cab- 

 bage heads, but somewhat weakly parasitic on 

 germinating plantlets and rapidly growing 

 seedlings. 



The writer has observed that seedlings of 

 the varieties All Season and Market Garden 

 are early and quite susceptible to this fungus. 



A preliminary bulletin is being prepared 

 calling attention to the nature of the disease, 

 and to practises which are useful in avoiding 

 both the Phoma wilt and the Fusarium wilt. 

 The investigations on these diseases will be 

 continued. 



Thos. F. Manns 



Depabtiient of Botany, 

 Agbicuxtubai, Expebiment Station, 

 Woosteb, Ohio, 

 September S, 1910 



SOCIETIES AND ACADEMIES 



the AMERICAN MATHEMATICAL SOCIETY 



The one hundred and fiftieth regular meeting 

 of the society was held at Columbia University on 

 Saturday, October 29, extending through the usual 

 morning and afternoon sessions. Forty-three 

 members were present. E.x-president W. F. Os- 

 good ocupied the chair at the morning session, 

 Kxpresident H. S. White and Professor Edward 

 Kasner at the afternoon session. The following 

 new members were elect<'d: Dr. G. A. Campbell, 

 American Telephone and Telegraph Company; 

 Mrs. E. B. Davis, Nautical Almanac OlKce; Pro- 

 fessor C. W. Emmons, Simpson College; Professor 

 H. C. Feemster, York College; Mr. R. R. Hitch- 

 cock, University of North Dakota; Mr. W. J. 

 Montgomery, University of Michigan; Professor 



