— 172 — 



then mapped out, and the very numerous details were placed in 

 the hands of a competent observer in our laboratory.'^ 



GENERAL CHARACTERS. 



We adopt the name " lycaf-blight " for the malady in question, 

 as it is a name not only frequently heard, but is appropriate con- 

 sidering the origin and the effects of the disease. Of the various 

 other names found in various publications, the most descriptive is 

 the "spot disease," given on account of the appearance of the 

 blighted areas on the leaf. The names "sun-burn," "sun-scald," 

 " strawberry rust," are also frequently applied, and the enumer- 

 ation of the above will recall to the mind of an}' strawberry grower 

 this troublesome disease. 



In all sections, it is generally conceded that this blight appearis 

 on the new leaves about the time the fruit sets, and if it goes on 

 unchecked is at its worst during the hot weather prevailing just 

 after the crop is gathered. If continuous cloudy and rainy weath- 

 er in May and June, causing a rank growth of leaves, is succeeded 

 by hot, dry weather in July and August, the strawberry suffers a 

 great check ; and if it has also been exhausted by a large crop, it 

 is, in this state of weakened vitalit}', usually attacked with great 

 severity by the fungus, Sphaerella Fragarice. 



The latter, like many of the flowering plants, has various stages 

 of development, each of which taken by itself exhibits character- 

 istics very different from any of the others. The observations and 

 experiments made last winter and spring showed the following 

 stages of growth and reproduction, all proven to be connected : 

 first, the vegetative stage, or that of the mj-celium ; second, the 

 early conidial stage ; third, the scleroiium stage, — a winter conidial 

 stage ; fourth, the perithecium stage. The spores or reproductive 

 bodies of the second and third are extremely abundant, but short- 

 lived ; those of the fourth stage, being "resting" spores, are few 

 but of comparatively long duration. 



* Miss J. W. Snow, holder of one of the University Fellowships during 

 188S-1889, desiring to inform herself concerning methods in work of this 

 nature, undertook and carried on from October, 188S, till June, 1889, the ob- 

 servations, artificial cultures and infections. While the writer watched the 

 course of the work, and made some of the later experiments, most of the 

 new matter here given is drawn from Miss Snow's observations and records ; 

 and the figures after Fig. 2 are from original ones made by her. A long 

 series of experiments on the possible development of sexual organs and py- 

 cnidia, and on the growth of the perithecium, are omitted here, as they are 

 not yet complete, and it is Miss Snow's intention to continue this investiga- 

 tion. 



