704 EXPERIMENT STATION RECORD. 



Seed sampling and testing, A. Clemext (Bthj. Hort. et Agr., 9 {1897), No. 4, 

 p. 57). 



The water hyacinth in Florida, 11. J. Webber {Florida Agr., 24 {1897), No. 8, 

 2). IIS). — Notes aie given of the iutroduction aud spread of this aquatic plant, with 

 some suggestions for jiossible relief. 



The Russian thistle in California, C. H. SiiiNX {California Sta. Rpt. 1895, pp. 

 277-J91, pis. .?).— A reprint of Bulletiu 107 of the station (E. S. R., 1, p. 130), 



Combating couch grass, J. C. Blewbury {Gard. Chron., ser. 3, 21 {1897), No. 

 524, p. 28). — By plowing the land hoth ways when dry, aud thorough harrowing, the 

 grass, etc., heiug removed and burned aud then seeded to harley or wheat, the 

 author claims to have eradicated couch grass. 



DISEASES OF PLANTS. 



A new disease of the peach, W. G. Johnson [Maryland Sta. Bui. 

 42,2)2). -^■^-) I'^'^j.Pi/-^- ■^)- — Duriug the ATork of inspecting the unrseries 

 of the State, the author has on three occasions observed peach seecUiiigs 

 in an unhealthy condition. The trees affected had a characteristic 

 reddish tinge, said to be due to the coloration of the underside of the 

 leaves, which have a tendency to roll upward and inward, exposing 

 the under surface. The reddish tinge first appears on the outer edge, 

 gradually spreading over the entire surface, giving the trees a decided 

 reddish appearance. So far, the cause of the disease has not been 

 ascertained, aud as no fungus or bacterial parasite is observed it is 

 thought to be probably due to soil conditions resulting in imperfect 

 nutrition. Whether the disease is communicable by budding is 

 under investigation, as well as other points concerning the vitality 

 and longevity of diseased trees. Experiments have also been under- 

 taken to see whether the diseased condition can not be remedied by 

 treating the soil with lime to neutralize the acidity, and stable manure 

 or some commercial fertilizer to supi^ly nitrogenous material. It 

 appears that the disease is worst in acid soils, and such should be 

 avoided in planting. 



Plant diseases, 0. W. Woodworth {California Sta. Ept. 1895, p2). 

 331-340). — Notes are given on crown knot, trunk kernel, twig knot, 

 powdery bark, gum disease of citrus trees, gum disease of stone fruit, 

 root rot, sour sap, blight or die-back, leaf curl, aud pear and apple scab, 

 aud the effect of alkali and of moss on orchard trees. 



The conclusions given in Bulletin 99 of the station (E. S. E., 4, p. 563) 

 relating to crown knot having been questioned, the author presents 

 additional evidence based on results of extensive experiments on this 

 disease. It is maintained that the disease is entirely distinct from any 

 other aud may be successfully treated with fungicides. It does not 

 seem to be connected in any way with external conditions, aud may be 

 absent for a considerable time, then suddenly appear and as suddenly 

 disappear. One of the earliest observations of the disease is its occur- 

 rence ou plow wounds, and it is said to be certain that there is no simi- 

 larity between normal healing of the wound and the crown knot. 



