1916] DISEASES OF PLANTS. 47 



Leaf stripe (HelmmtJiosporium gramine^im) appears not to have been 

 lessened Ity steeping the grain in formaldehyde of 0.1 per cent strength for 

 from 10 to 30 minutes, but copper sulphate of 0.5. per cent strength for the 

 same period reduced the disease considerably, and 1 per cent reduced attack 

 to about 0.5 per cent of the grain sown. Mercury chlorophenol and chinosol 

 also appear to be practical remedies for leaf stripe. 



Tests on the control of Fusarium in relation to the preservation of germi- 

 nability are considered to show tliat cliinosol is not to be recommended un- 

 reservedly in this connection, Uspulum, a trade preparation of mercury 

 chlorophenol, is said to have about equal value with corrosive sublimate, while 

 formaldehyde has somewhat less. 



Smut control, O. Appel {Mitt. Dcut. Landw. Gesell., 30 {1915), No. 37, pp. 

 551, 552). — This is a discussion of some methods for the control of grain smuts 

 which are claimed to be sufficiently safe, suitable, and inexpensive to warrant 

 their employment in the present situation in Germanj\ These include washing 

 the seed grain by hand, treating with from 0.1 to 0.2 per cent of formaldehyde, 

 and steeping in water at 45° C. (113° F.) for two hours or at 40° for from 

 six to eight hours, or a combined treatment by steeping in water at from 

 25 to 30° for four hours (or one hour and covering the grain from six to eight 

 hours) and then for from five to ten minutes in water at from 50 to 52°. 



[Grain rusts], E. Riehm {Dent. Landw. Presse, 42 {1915), No. ^9, pp. ^33, 

 434, pl- 1, fifj- !)• — This is a descriptive discussion of black rust {Piiccinia 

 graminis) on wheat, rye, barley, and oats; yellow rust (P. glumarmn) on 

 wheat, rye, and barley; brown rust (P. triticinu) on wheat; brown rust (P. 

 dispersa) on rye; crown rust (P. coronifera) on oats; and dwarf rust (P. sim- 

 plex) on barley. 



[Injurious influences affecting winter rye], K. Stokmee {Dent. Landiv. 

 Presse, J,2 {1915), Nos. 65, pp. 559-561; 66, pp. 572, 573, fig. i).— This is a dis- 

 cussion of weather, soil, and plant and animal parasites as affecting rye pro- 

 duction in 1914-15 in Pomerania, with more particular reference to Fusarium 

 as related to foot rot and to remedies therefor. A proprietary preparation of 

 corrosive sublimate is recommended as preferable to copper sulphate or for- 

 maldehyde in this region. 



Climatic conditions as related to Cercospora beticola, Venus W. Pool and 

 M. B. McKay {U. S. Dept. Agr., Jour. Agr. Research, 6 {1916), No. 1, pp. 21-60, 

 pis. 2, figs. 10). — The results are given of a study carried on at Rocky Ford, 

 Colo., from 1911 to 1913, and near Madison, Wis., during 1914, to determine the 

 climatic conditions of both winter and summer as bearing on the vitality and 

 development of C. heficola. Notwithstanding the differences in temperature and 

 soil moisture conditions, similar results were obtained from the overwintering 

 experiments at both places. 



When exposed to outdoor conditions, the conidia of the fungus die in sugar 

 beet top material in from one to four months, but when kept dry, they may 

 remain alive as much as eight months. The sclerotia-like bodies which are em- 

 bedded in the tissues of the host are more resistant than the conidia and live 

 through the winter when only slightly protected, becoming a source of infection 

 for the succeeding crop. 



Tests of artificial cultures showed that exposure to constant temperatures 

 of from 95 to 97° F. was fatal to the growth of the fungus, but that when ex- 

 posed for three days to either of these temperatures and then changed to 87°, 

 growth followed, as was also the case when cultures were held at either of 

 these temperatures for eight hours and then at 68° for 16 hours. A temperature 

 of 105° was found fatal in all combinations tested. 



