316 



Pomona College Journ.vl of Economic Botany. 



disease could be communicated by cuttings and that the spores of the fungus 

 were capable of retaining their vitality for several months. Sterilization of 

 the soil vi^hen convenient, the use of cuttings from sound plants, and the 

 immediate removal of diseased plants from the beds were recommended to 

 prevent attacks of the disease. The Fusarium causing the disease was isolated 

 in pure cultures, but only one form of spore developed, and it was fusiform, 

 pointed at both ends, hyaline, slightly curved, 3-5 septate and measuring 

 25 u.*-38 U.X3.5 u.-4 u. These spores were borne singly or in small clusters, 

 on the tips or sides of short branches of mycelium and, when seen in mass, they 

 present a pale salmon pink color. A few inoculation experiments were tried. 

 No infections were obtained by injecting Fusarium spores into incisions made 

 on the plant. The inoculations made through the soil were indefinite. 



In the same year the disease was brought to the attention of F. W. Card 

 and J. E. Adams, of the Rhode Island Station. In 1898 they performed an 

 experiment with fifteen hundred cuttings of a very susceptible variety (Flora 

 Hill). Cuttings were grown in clean sand and in sand on which carnations 

 had been previously grown. Chemical fertilizers and stable manures were 

 compared, and the effect of dipping cuttings in Bordeaux mixture before 

 planting was tried. The most marked results were obtained in the use of 

 fresh, clean sand. Dipping the cuttings in Bordeaux mixture resulted in con- 

 siderable loss. The general belief that the stable manure in the soil favors the 

 progress of the disease was not sustained. 



A more complete account of the disease and the organism causing it is 

 given by L. INIangin and IM. G. Delacroix of the Paris Academy of Science in 

 No. 19, Vol. 129, and No. 23, Vol. 131, of Comptes Rendus. 



In the fall of 1899, the disease was reported to be causing considerable 

 damage to the fields of carnations at Nice, Provence, and Antibes. Mr. L. 

 Mangin describes the disease as starting in the young stem and spreading out 

 to the leaves, causing a serious decomposition of the stem, and a wilted and 

 yellowish appearance of the leaves. The roots appear to be healthy. In a 

 microscopical examination of the diseased stems, a large number of organisms 

 were found in the decomposed, brown, and rotted areas, but only one was 

 persistently found in the green tissues. This was a colorless mycelium extremely 

 well developed in the cambium layer, and best observed in a thin longitudinal 

 section of the stem. Parts of affected stems placed in a moist chamber became 

 covered with a white mycelium and formed two varieties of conidia. The 

 larger conidia were fusiform, curved, and often pointed; they are divided by 

 transverse septa from 1-5, but ordinarily 3 in number. Their dimensions vary 

 between 20 u. and 30 u. in length, by 2.5 u.-5 u. in width. The smaller spores 

 were observed in the crevices of the stems and in the white areas of the rotted 

 spots. These conidia were almost cylindrical, slightly curved, and rounded 

 at the ends. They were 5 u.-12 u. in length by 2 u.-3 u. in width, and 

 without septa. Chlamydospores developed in cultures fifty days old. These 



*u used by typist for micromillitneters. 



