DISEASES OF PLANTS. 845 



Further examination of material previously studied has shown that the 

 resting stage of S. endobioticuvi is not of common occurrence. 



Beet tumors, J. I'eklo {Ztschr. Zuckerindus. Bohnicn, 39 (1915), No. 5, pp. 

 204-219, figs. 5). — The author describes the tumors resulting? from the inocula- 

 tion of sugar beet with BacteHum beticohun, obtained for this purpose from 

 Smith after his discovery of this organism (E. S. R., 25, p. 243). B. tume- 

 faciens was also used to inoculate various plants. The results, such as tumor 

 formation, infection strands in stems, etc., are discussed, with emphasis on the 

 similarities between the results as shown in beets, for example, and those 

 in animals and human beings. 



Relation of stomatal m.ovement to infection by Cercospora beticola, Venus 

 W. Pool and M. B. McKay (U. S. Dcpt. Agr., Jour. Agr. Research. 5 {1916), No. 

 22, pp. 1011-1038, pis. 2, figs. 6).— The results are given of a study of leaf infec- 

 tion of the sugar beet caused by C. beticola. 



Infection was found to be determined by certain morphological and environ- 

 mental factors which influence stcmiatal activity. Among the factors concerned 

 in the movement of stomata are leaf maturity, light, temperature, and relative 

 humidity. Infection, both artificial and natural, was found to occur best on 

 mature leaves and to be influenced by the rapidity of germ tube growth, ma- 

 turity of leaves, and stomatal movement. Penetration of the leaf by the conidial 

 germ tubes of C. beticola has been observed to occur only through open stomata, 

 and consequently it is thought that infection probably takes place during day- 

 light hours. As soon as penetration of the germ tube occurs, an attempt is 

 made by the leaf cells to isolate the invading organism, but when this is not pos- 

 sible the fungus grows and produces a well-defined leaf spot. 



A fungus of uncertain systematic position occurring on wheat and rye, 

 P. J. O'Gaba (Science, n. ser., 43 (1916), No. 1099, pp. Ill, 112).— A report is 

 given of a fungus which is found attacking the heads of wheat and rye some 

 time before they emerge from the leaf sheaths. Often the heads are said to be 

 so severely attacked that they do not emerge but remain permanently within 

 the sheath. The organism has been isolated and grown in pure cultures, but 

 its identification has not been fully determined. 



Fungus diseases of wheat, G. P. Darnell-Smith and E. Mackinnon (Dept. 

 Agr. N. S. Wales, Fanners' Bui. 102 (1915), pp. 3S1, figs. 28).— This consists of 

 information and suggestions regarding control, as condensed from various 

 sources, relating to fungus diseases of wheat in New South Wales. These 

 include bunt or stinking smut (Tilletia tritici or T. levis), loose smut (Ustilago 

 tritici), flag smut (Urocystis tritici), rusts (Puccinia graminis and P. tri- 

 ticina), mildew (Erysiphe graminis), take-all (Ophiobolus graminis), ergot 

 {Claviceps purpurea), and blight associated with several species of Septoria. 

 A form of contortion described is attributed to insect attack or to dispropor- 

 tionate growth in two different directions. 



Seeding time and attack by stinking smut, J. Appl (Ztschr. Landw. Ver- 

 suchsw. Osterr., 18 (1915), No. 3, pp. 45-54). — Results are given of studies on the 

 influence of fungicidal treatments of seed wheat on subsequent attack by 

 stinking smut, and also on the effects of seeding time and weather in this 

 connection. 



It is stated that the germination of wheat seed at the temperatures prevalent 

 during the early part of October results in a higher percentage of attack by 

 stinking smut than does that of seed planted earlier. By planting after 

 October 30, however, the percentage of attack was diminished, owing probably 

 to the fact that the fungus germinates at a somewhat higher minimum tempera- 

 ture than the seed, thus permitting the cereal to pass its period of greatest 

 susceptibility comparatively free from attack. 



