DISEASES OF PLANTS. 849 



due to B. ribis, and its life liistoiy and some of the more imi)ortant points in its 

 biology have been worked out. 



The fungus infects and liills young currant shoots about the time they have 

 completed their elongation grovyth, and it may cause older branches and parts 

 of bushes to wilt throughout the summer, due to the advance of the fungus from 

 the shoots infected during former seasons. 



As noted above, the disease was first considered due to a sterile fungus, no 

 spores having been observed on currant bushes or in pure cultures, and the 

 authors find that there is no spore formation present when a branch wilts except 

 occasionally at the point where the parasite enters. The investigations showed, 

 however, that 3 types of spores are developed on the host, although the fungus 

 usually remains sterile in pure cultures. Several fungi may appear saprophyt- 

 ically on the dead bushes, and one of the most prevalent, N. dnnaharina. has 

 been considered the cause of the disease. 



As the study of the life history of the fungus shows that the spores are pro- 

 duced on dead stems and branches of the host and that the currants are most 

 commonly infected in midsummer, it is believed probable that the disease may 

 be checked or reduced by carefully pruning blighted plants during May, instead 

 of practicing winter pruning, as is at present customary. All prunings should 

 be burned instead of allowing them to lie upon the ground during the summer. 



A fungus disease of Ribes aureum, Rottger (Deut. ObstMu Ztg., 1911, No. 

 H, pp. 236, 237). — Attention is called to a disease of this currant, due, it is 

 claimed, to Camarosporium riMs, which produces circular spots on the epidermis 

 of young, nonwoody twigs. 



On a disease of Ribes species due to Botrytis cinerea, F. Krause (Deut. 

 Obtslbau Ztg., lUll, Xo. U,, pp. 231-239, figs. 3).— The author holds that the cause 

 of the disease of R. aureum noted above, as well as of other species and crosses 

 of Ribes, is due to B. cinerea, as the sclerotia of this fungus was obtained from 

 the diseased bark and also from the pith of the attacked stems. 



The ascogenous form of tlie fungus causing dead-arm of the grape, C. L. 

 Shear {PhytopatJiology, 1 {1911), No. J,, pp. 116-119, figs. 5).— The author 

 reports the finding of an ascogenous form associated with the pycnidia of 

 Ftisicoccum viticolum, which is believed to be the perfect stage of this fungus. 



Cultures from ascospores of this pyrenomycete, which is apparently a species 

 of Cryptosporella, produced pycnospores and scolecospores practically identical 

 with those produced from the pycnospores of F. viticolum taken from grapevines 

 diseased with dead-arm. The fungus is tentatively called Cryptsporella viticola 

 n. sp., and a description is appended. 



Chlorosis and mildew, G. Provost-Dumarchais (Jour. Agr. Prat., n. ser., 22 

 {1911), No. 28, pp. .'f3, 4'i)' — It is claimed that the unusual wet season of 1910 

 caused an abnormal amount of lime to be present in the soil water. On being 

 absorbed by the grape roots this produced a diseased or weakened condition of 

 the vines, thereby making them more susceptible to the attacks of the mildew. 



[Double flower in dewberries and blackberries] {North Carolina Sta. Rpt. 

 1910, pp. 10, 11). — ^A brief account is given of investigations on the double 

 flower of dewberries and blackberries, the cause of which is due apparently 

 to the presence of a fungus in the flower bud. The relative resistance of 

 different varieties is being studied, and some work is in progress on other 

 methods of control. 



A new raspberry disease, H. Rosenthal {Deut. Obstbau Ztg., 1911, No. I4, 

 pp. 289, 240, figs. 2 ) .—Attention is called to a disease of raspberries which 

 attacks the young shoots in the early summer, producing brown spots on them 

 and causing them to become long, slender, and almost leafless. The cause of 

 this disease is not given, but it is supposed to be due to the attack of a fungus. 



