DISEASES OF PLANTS. 743 



tion regarding some of the more common root rots of ginseng, those ilescribed 

 being tlio wilt (Acrofitahifjiniis panac), black rot (Scleroiinia sp.), end or fiber 

 rot (Thielavia basicola), soft rot {Bacterium sp. and Fusarium sp.), end or red 

 rot (Bacillus araliavorns), crown rot (Sclerotinia lihertiana), damping off 

 (Rhizoctoniu sp.), and nematode galls. 



The control of onion smut, G. E. Stone (Massachuttctts 8ta. Virc. 21, pp. 2, 

 figs. 2). — In experiments on controlling the onion smut, positive results were 

 obtained by applying per acre 100 lbs. of sulphur thoroughly mixed with 50 

 lbs. of air-slaked lime in the drills. Ground lime drilled in with a fertilizer 

 drill at the rate of 75 to 100 bu. per acre is also good, but the best results were 

 obtained by the use of either 1 lb. of formalin to 30 gal. of water, or 1 oz. to 1 

 gal. of water, applied when the seeds are sown with an appliance previously 

 noted (P:. S. R.. 22. p. 244). 



Disease resistance of potatoes, W. Stuaki (Ann. Rpt. Com): Agr. Vt., 1 

 (1909), pp. lOS-109). — In a general discussion of the results of investigations 

 and exi)eriments with a number of European varieties of potatoes imported in 

 1905, it is claimed that the characteristics which seem to be associated with 

 the more strongly marked disease-resistant varieties are an erect habit of 

 growth, a stiff, upright, and woody stem, and, in most cases, hairy leaves. 



Investigations on the leaf-roll disease of the potato, G. Bohutinsky- 

 Krizevci (Moiiatsh. Landii:., 2 (1009). p. 118; abs. in Ccntbl Bakt. [e^c], 2. 

 AM., 2It (1909), A"o. 23-25, pp. 575, 576). — From experiments and observations 

 on this disease, the author reaches the following conclusions: (1) The rotting of 

 the stems of the potato plants is a secondary phenomenon; (2) the disease 

 originates from injuries to the roots caused by the attacks of a fungus, whether 

 aided in its entrance by a weakened condition of the plants, or by weather condi- 

 tions which cause an intensive grow'th of the fungus in the soil, being as yet 

 undetermined; (3) the fungus usually attacks, at first, solitary plants, and then 

 spreads from these until many plants become diseased. 



Enzymatic disturbances of the seed tubers, which show themselves in a curling 

 of the leaves of potatoes grown from them, were not observed. The seed 

 tubers of most leaf-roll diseased plants are usually sound, even when the dis- 

 eased plants produced from them have died down. 



The injuries produced by the fungus cause the death and subsequent rotting 

 of the roots of the plants, while the decomposition products are transported by 

 the fibrovascular bundles to the stems, stolons, and tubers, producing a brown 

 discoloration of the vascular regions in these parts. 



The disease has apiteared suddenly in different localities in Croatia and 

 Slavonia where previously it had not been observed. It attacks plants grown 

 from seed as well as those propagated from tubers, and completes its develop- 

 ment from the infectious stage to the complete destruction of the i)lants in a 

 single year. 



The disease can probably be carried over from year to year by means of the 

 mechanical adhesion of the spores of the fungus to the surface of the tubers, 

 and also by the remnants of infected stolons which cling to the seed potatoes. 

 In either case, disinfection of the seed tubers would be of value in controlling 

 the disease, although, as would be expected, the fungus found in the soil itself 

 would reinfect the disinfected seed under conditions favorable to its growth. 



On the history of the leaf curl or ring disease of the potato, C. Hugues 

 (Agr. Goriziano, (1910), No. 13, pp. 1, ^).— From a study of the literature 

 on this subject, the author claims that the leaf curl or ring disease of the 

 potato is not a recently introduced disea.se, as some authors claim, but that as 

 far back as 1780 there was a serious ei)idemic, esi)ecially in Germany. 



