DISEASES OF PLANTS. 47 



Infection studies with Peronospora, G. von Istvanffi and G. Palinkas 

 (Ccntbl Bald, [etc.], 2. Abt., 32 {1912), No. 20-25, pii- 5o-Z-50'-i).— Continuing 

 previous investigations (E. S. R., 25, p. 751), the authors made a study of 

 Peronospora on beet and grape leaves by artificial infection of separated leaves 

 and of plants growing in the open in wet and in dry weather and at varying 

 temperatures, in order to ascertain the period of inoculation and the influence 

 of relative humidity, temi>erature, and condition of the plant on its liability 

 to develop the infection. 



It was found that rapidity of development was variable, and that high rela- 

 tive humidity of the air, high water content of the plant, and sudden lowering 

 of temperature all tended to render the plant more open to attacks by the 

 fungus. Dryness tended to retard advance of the disease when already present. 



The infection of forage grasses by ergot, E. Gain (Compt. Rend. Soc. Biol. 

 [Paris], 72 (1912), Ao. 5, pp. 189-191). — It having been claimed that the spores 

 of certain ergots, especially tliat of Lolium, require passage through the intesti- 

 nal tract of insects to secure their germination, the author conducted some 

 exi^eriments with about 30 specimens of L. perennc, Arrhenutherum elatiiis, 

 Phlcum pratense, and Holctis lanatus to determine the rule of insects in tlie 

 sjjread of ergot among these grasses. 



Inoculation experiments showed that ergot could be readily produced, but that 

 insects played a secondary role, merely acting as carriers of the spores as in 

 pollination, and that they were not essential to tlie dissemination of tlie fungus 

 or to the infection of the host plant. 



The use of iron sulphate for the control of the rust of plants, C Fuschini 

 (Rivista [Concgliano], .'/. ser., 17 {1911), No. ID, pp. ////3-//.'/6"; abs. in Intcrnat. 

 Inst. Agr. [Rome], Bui. Agr. Intel, and Plant Diseases, 2 (Wll), No. 11-12, p. 

 2600). — A preliminary account is given of experiments by the author on the 

 application of considerable quantities of iron sulphate to the soil for the pre- 

 vention of the rusts of wheat and beans. 



In the experiments iron sulphate was added to the soil at the rate of 1.6 

 cwt. per acre for wheat and 2.4 cwt. for beans, after which the seed was planted. 

 No difference could be noted for the wheat the following season, as there was 

 but little rust in the vicinity. With the beans there was a considerable increase 

 in weight of both tlie seed and plants. This is attributed to the use of the iron 

 sulphate, which induced a much more vigorous vegetative growth. 



The author is of the opinion that the application of iron sulphate before 

 planting may be of use in preventing rusts in various crops through the general 

 increase in the vigor of the plants, so that they can better resist the attacks of 

 fungi. 



A practical view of root rot of beets, H. Briem (Ztschr, Zuclcerindus. 

 Bohmen, 36 {1911), No. 1, pp. 23-25). — After a brief discussion of some opinions 

 regarding the nature of this disease and remedies therefor, the author states 

 that his experience leads him to the conclusion that a plentiful supply of lime 

 in the soil in available form and the thorough aeration of the soil by means of 

 the hoe are the most effective means for combating this disease. 



Rice blight, J. S. Colliek {Illinois Sta. Circ. 156, pp. 19, figs. 11). — In con- 

 tinuation of a previous report (E. S. R., 24, p. 743) and preliminary to an 

 extended statement giving the entire data and the results of the experiments, 

 the author gives an account of his investigations on rice fields in Arkansas. 



The disease seems to be wholly a physiological one, and is not to be con- 

 founded with blights caused by insects or fungi. The root is the part of the 

 plant affected, and the nutrition of the plant is so impaired that the grain does 

 not develop. The results show that a good physical condition of the soil, with 

 aeration at the proper time, will prevent blight. It is not caused by deep 



