1918.1 DISEASES OF PLANTS. 753 



must have been limited or else that the weather conditions In this vicinity were 

 specially favorable this year. A similar rust is said to have appeared previ- 

 ously in California, Lower California, Mexico, Falfurrias, Tex,, and Miami, 

 Fla. 



Peronospora on hemp, V. Peglion (Atti R. Accad. Lincei, Rend. CU Sci. Fis., 

 Mat. e Nat., 5. set:, 26 {1917), I, No. 11, pp. 618-620).— The author reports hav- 

 ing noted the presence of oospores in various cultures of a fungus on hemp 

 which has been referred to Peronospora. On the basis of studies of this and 

 related forms he holds that this organism should be referred to the subgenus 

 Peronoplasmopara proposed by Clinton (E. S. R., 17, p. 156). 



Conditions influencing the distribution of potato blight in India, J. F. 

 Dastub (Agr. Jour. India, Indian Sci. Cong. No., 1917, pp. 90-96). — The author 

 discusses further (E. S. R., 35, p. 150) the history of potato late blight {Phy- 

 tophthora infestans) in various parts of the world as evidencing its inabilty 

 to exist continuously at points having prolonged periods of temperature much 

 above 77° F. He states that on the plains of India the fungus is normally un- 

 able to survive in soil or tubers, so that potatoes ordinarily susceptible to this 

 disease may be grown if they are imported in summer when the temperature 

 is sufficiently high to kill the fxmgus. 



A potato parasite new to Italy, B. Peyronel (Atti R. Accad. Lincei, Rend. 

 CI. Sci. Fis., Mat. e Nat., 5. ser., 26 (1917), I, No. 9, pp. 509-512).— In the course 

 of work with potatoes supposed to be completely sterilized in preparation for 

 other work, a fungus appeared on the surface of the tubers which was found 

 to be Spondylocladium atrovirens and which is briefly discussed. Since that 

 time the author has seen this fungus in potato tubers produced elsewhere in 

 Italy. 



Irrigation experiments on apple spot diseases, C. Brooks and D. F. Fisher 

 (V. S. Dept. Agr., Jour. Agr. Research, 12 il91§). No. 3, pp. 109-lSS, pis. 4, 

 figs. 10). — This paper deals with the effect of soil water supply upon bitter 

 pit, Jonathan spot, and certain other nonparasitic spot diseases of the apple. 

 It also includes notes upon the relation of the time of picking to the development 

 of apple spots in storage. The experimental work on this investigation was 

 carried on in the State of Washington. 



It is claimed that bitter pit and Jonathan spot are readily distinguished 

 from rosy-aphis stigmonose, drought spot, cork, and blister, bitter pit usually 

 appearing first as spots of dead brown tissue in the subepidermal tissue of the 

 apple. These spots are associated with tlie terminal branches of the vascular 

 bundles, and in the later stages of the disease the browning often follows the 

 vascular bundles deep into the flesh of the apple. Rosy-aphis stigmonose is 

 said to be characterized by similar brown spots, the affected tissue being 

 firmer than in the case of bitter pit and there being no association with the 

 vascular bundles. The early stages of Jonathan spot are said to be confined 

 to the color-bearing cells of the skin of the apple. Drought spot is characterized 

 l)y the checking of the growth at certain points on the apple without the pro- 

 duction of any large quantity of corky tissue. Cork differs from drought spot 

 in the presence of comparatively large areas of corky brown tissue and in the 

 fact that these areas are usually rather deeply seated in the flesh of the apple. 

 Blister is the name given to superficial lesions associated with cork and charac- 

 terized by a blister-like appearance. 



Drought spot is said to be produced by sudden and extreme drought. Cork is 

 apparently a drought effect, but it differs from drought spot in that its occur- 

 rence is usually associated with certain peculiar soil types. 



