254 Pflanzenkrankheiten, 



Baiiey, F. D„ Notes on potato diseases from the North- 

 west. (Phytopathology. IV. p. 321-322. 1914.) 



A brief communication about three potato diseases: 



Silver scurf, caused by Splondylocladiurn otrovirens Harz., was 

 observed on both early and late plantings on new ground in Al- 

 banj^ Oregon, and during the fall of 1913 also in man}' other 

 parts of the United States. 



Stysanus stemonitis (Persoon) Corda was reported as the cause of 

 a serious disease in Oregon. 



A case of what appeared to be mushroom root rot, Arunllarm 

 mellea Vahl., was sent by a grower in Clark County, Washing- 

 ton. The rhizomorphs were firmly attached at several points each 

 of which was the center of affected area, from where decaj^ sprea- 

 ded. The ground on which the crop was raised was comparatively 

 new and contained fir roots on which an abundant development of 

 rhizomorphs was observed. The loss was of little consequence in 

 the potato field. M. J. Sirks (Haarlem). 



Brooks, C, Blossom-end rot of tomatoes. (Phytopathology. 

 IV. p. 345-374. 3 pl. 1914.) 



The experiments reported in this paper seem to justify the fol- 

 lowing conclusions, made by the author: 



1. The blossom-end rot of the tomato is not due primarily to 

 bacteria or fungi. 



2. Plants are most susceptible when in a condition of great 



activity. 



3. Eilher continued excessive watering or a sudden check in 

 water supply may produce the disease. 



4. With liberally watered greenhouse plants potassium Chloride 

 increases the disease and lime and sodium nitrate decrease it. These 

 facts have not been found to hold true under field conditions. 



5. Ammonium sulphate, dried blood and cottonseed meal have 

 increased the disease more than sodium nitrate containing an equi- 

 valent amount of nitrogen. 



6. Heavy applications of horse stable manure have increased 

 the disease out of proportion to the increase in vigour of the plants. 



7. When well supplied with water plants on a sandy leam have 

 developed less disease than those on a clay leam. 



8. Raising the soil temperature of the greenhouse plants has 

 increased the disease, 



9. The writer is of the opinion that the increase in the disease 

 from heavy watering is due to the development of harmful humic 

 and ammonium Compounds and an accompanying decrease in 

 nitrates. 



10. Susceptible tissue has more starch and more oil than normal 

 tissue and its cell sap has a higher osmotic value. 



11. The protoplasm in the cells from the fruit of the heavily 

 watered plants is more granulär and contains more oil than that 

 of the lightly watered ones. M, J. Sirks (Haarlem). 



Byars, L. P., Preliminary notes on the cultivation of 

 the plant parasitic nematode, Heterodera radicicola. (Phy- 

 topathology. IV. p. 323-326. 1914.) 



In Order to investigate under optimum conditions the relations 



