-DISEASES OF PLANTS. 159 



vention of the peach-leaf curl, jiluni rot, peach rot, downy mildew of the grape, 

 cucunil)er and muskmelon downy mildew, and apple-tree canker. 



Studies in smut diseases of cereals and their prevention, C. von Tubeuf 

 {Arb. K. Gesundheitsamte, Biol Ahf., 2 {1901), No. 2, pp. ^75-^-^9).— A description is 

 given of the principal smuts affecting cereals, and suggestions given for their pre- 

 vention. 



New species of Uredinese, J. C. Arthur {Bui. Torrey Bat. Club, 28 {1901), Xo. 

 12, pp. G61-G66). — The author describes a number of new forms of Uredineae which 

 have been sent him from various localities in the United States, the type specimens 

 of which are retained in its herbarium. The species described are as follows: Puc- 

 cinia batesiana, P. epicampus, P. .vylorrhizx, P. vilis, P. pmniculariiv, .Fxidimn boltonm', 

 A.mngnahim, A. anognv, Peridermlum ornamentale, Oymnosporangiuvi nelsoni, R(rstelia 

 nelson i, P. fimbr'mla. 



A new disease of alfalfa, G. Pollacci {Separate from Aiti InM. Bot. Univ. Pavia, 

 VII, pp. 6, pi. 1; abs. in Ztschr. Pfianzenkrank., 11 {1901), No. 4-5, pp. 285, 286).— K 

 disease of alfalfa is described which is said to be due to an undescribed fungus to 

 which the author gives the name Pleosplnerulina briosiana. This fungus forms ash- 

 gray spots with brownish borders on the leaves. The spots increase and run together, 

 finally destroying the leaves. In addition to alfalfa, it is reporteil as occurring on 

 the related species { Med Imyo falrafa) . 



Clover anthracnose, B. Mehnek {Ztschr. Pjlanzenkrank., 11 {1901), No. 4-5, pp. 

 193-196). — During the summer of 1901 clover anthracnose was noted in a number of 

 localities in Germany as affecting the red clover. The disease in some regions proved 

 very destructive, 25 or 30 per cent and sometimes more of the plants being killed. 

 The fungus which causes the disease was identified as Glaosporium trifolii. Investi- 

 gations made on the disease seem to indicate that it spreads during the growing sea- 

 son by means of the conidia, and that it survives the winter as mycelium and in 

 pycnidial form in the tissues of the clover plants. This disease is thought to have 

 been introduced from America tlirf)Ugh clover seed, and is more destructive to plants 

 grown from American than from German seed, the American being a more hairy 

 plant, is more subject to disease. 



Potato failures, F. M. Rolfs {Colorado Sta. Bid. 70, pp. 20, pis. 12). — Numerous 

 inquiries had been received from potato growers regarding a failure of the crop, 

 and investigations showed that the trouble was due to attacks of Rhizoctonia solani 

 (E. S. R., 13, p. 55), which is an active parasite of the j)otato plant. The annual 

 loss in the State from this disease is quite large, and it is reported as quite common 

 in the i)otato fields of New York, Ohio, Iowa, Minnesota, Florida, Oklahoma, Texas, 

 Colorado, California, and Washington. The effect of the fungus on the potato plants 

 is described, one of the common results being the formation of an abnormal numl)er 

 of very small potatoes of no marketable value. The organism is peculiarly a soil 

 fungus, and the disease may be transmitted through the use of infected seed. Inoc- 

 ulation experiments are reported in which the disease was readily produced. Exam- 

 ination of a lot of potatoes during the planting season showed that 91 per cent were 

 more or less covered with sclerotia of the fungus. The disease may be carried not 

 only by potatoes but also by beet roots, dead potato stems, or on the dead stems of 

 many weeds which grow in potato fields. The results of seed treatment with corro- 

 sive sublimate and formalin solutions indicate that the diseased potatoes may be 

 readily disinfected by such treatment, but in order to secure good results the treated 

 seed must be planted in soil which is free from disease. When a field has become 

 thoroughly infected with the disease the fungus will doubtless remain in the soil for 

 a number of years. Attention should be paid to the sorting and disinfecting of the 

 seed tubers, and by practicing a long and systematic rotation of crops the soil may 

 be prevented from becoming badly infested with this fungus. 



