DISEASES OF PLANTS, 1055 



new a period of liicuhntioii takes i)lace. which may be lengthened more or less 

 uirordiiij; to the temperature and other conditions in the spring. 



In conclusion the author says that as the severity of the winter nuist affect 

 the amount of healthy host tissue that survives the winter, it must also limit the 

 amount of mycelium and the number of uredospores in the spring, and that this 

 ill all probal)ility is one of the chief factors in determining the violence of early 

 iiutlireaks of rust. 



Treating seed grains for the prevention of smut, K. A. Moore and A. L. 

 Sto.ne i]Vi.sco)t,sbi Sta. Rpt. 1906. pp. 210-21. ), fig. 1, dgm. 1). — Experiments 

 were carried on by the authors to lessen the loss caused b.y smut diseases of 

 barley. The treatments included soaking the seed grain in formaldehyde and 

 corrosive sublimate solutions, and a modified form of the hot-water treatment. 



The formaldehyde and corrosive sublimate treatments were effective in con- 

 trolling the form of smut known as closed smut, but they were without elTect 

 for the loose snnit of barley. For this the authors recommend soaking the seed 

 grain for 12 hours in cold water, after which it is submerged for from 5 to 20 

 minutes in water at a temperature of 130° F. As this treatment is etBcient for 

 both forms of smut, it is recommended for combating smut diseases of barley. 



A contribution to the biology of ergots, R. Stager (Coithl. Bakt. [etc.], 

 2. Abt.. 11 (IDOl), \o. 22-2'f. pp. 113-lHJf). — Inoculation experiments were car- 

 ried on for 2 years with conidia and sclerotia of Claviceps on ^esleria cccrnlea 

 from diffei'ent localities to determine the possibility of biological races of this 

 sjjecies. A considerable number of species of grasses were inoculated, but on 

 only a few were the inoculations successful. The results obtained show the 

 apparent identity of the ergot from 2 localities, the differences attributed being 

 due to climatic conditions. Based upon his experiments the author giv^s an 

 amended description of the biological race occurring on .S. ccerulea. 



Infection experiments with Erysiphe graminis, G. M. Reed {Trans. Wis. 

 Acad. Sci., Artx. and Lrttrrs. lo (1!)0',). pi. I. pp. J3.5-i62).— The author con- 

 ducted a series of inoculation experiments, using the conidia of E. graminis 

 from blue grass and rye, and as host plants rye, wheat, oats, barley, squirrel tail 

 barley, smooth brome grass, various species of Poa, rye grass, tall meadow 

 fescue, orchard grass, timothy, floating manna grass, etc. 



In the experiments with conidia from blue grass it was found that the mildew 

 on I'lxi pratciisis will not readily infect the other species of Poa experimented 

 with, ruder certain conditions it seems to be able to pass over to some extent 

 to /'. ncmonilix and in a still less degree to P. trivialis and P. compressa. In 

 tlie experiments with conidia from rye no inoculations were successful except 

 on the control rye plants. In all the experiments the seedlings of rye which 

 were inoculated with conidia from rye uniformly became infected, and this was 

 also true when blue grass was inoculated with conidia from blue grass. When 

 inoculations were made on other host plants in nearly every instance there was 

 no infection. 



The experiments confirm the general conclusion that spores of th(^ mildew 

 from one grass will not infect a grass belonging to a different genus. It seems 

 probalile that for E. graminis at least there is one if not more distinct species 

 for each genus of grasses, and in some instances there may be a number of 

 Iiliysiojogical forms upon tlie various sjiecies of the same genus. 



Further researches on brusone of rice in 1905, T*. Brizi {Ann. 1st. Agr. 

 \ Milan]. 6 ( Itlol-lflO.')). pp. Gl-103. figs. (i). — The experiments previously carried 

 on by the author had indicated that brusone may be caused by physiological 

 conditiniis. In the experiments upon which the present article is based, this 

 problem was tested on a larger scale with .'{ varieties of rice, which showed 

 considerable differences in their resisting power toward unfavorable conditions 



