19171 DISEASES OF PLANTS. 655 



being applied about tbree weeks after the petals have fallen. Summer-strength 

 lime-sulphur solution may be substituted for Bordeaux mixture where the dis- 

 ease is not severe, thus lessening the risk of injury. 



Apple scab control in British Columbia, R. M. Winslow {Canad. Hort., 

 40 {1911), No. 2, pp. S2, 56-58, fig. 1). — The rapid spread of apple scab in Brit- 

 ish Columbia during the last three years is said to have caused much alarm, 

 discouraging some very careful growers. In view of the losses of 1915, an 

 extensive series of tests was carried out in 1916 with lime-sulphur, which was 

 applied when the leaves were from i to i in. in length, when the blooms were 

 just about to open, when the blooms were falling, and again 14 days later, the 

 last three of these sprays proving to be of the greatest general utility. A wet 

 July makes a summer spray advisable, in addition to those above mentioned. 

 An abnormally bad year for scab may be followed by one almost free therefrom. 

 The sprays increased the percentages of absolutely clean and marketable fruit, 

 the average weight of the fruit, the total yield, the set of fruit, and the vigor 

 of the foliage. Tests with Bordeaux mixture and with atomic sulphur gave less 

 favorable results than those with lime-sulphur, which gave fair control of scab 

 even when unsprayed trees showed from 98 to 100 per cent infection. 



The biology of Exoascus deformans, A. Manakesi (Riv. Patol. Teg., 7 

 (1915), No. 7, pp. 19S-201).— The author during 1912 to 1915 made a study of 

 several varieties of peach in the Province of Bologna as affected by E. de- 

 formans, the cause of leaf curl, in connection with the weather during that 

 period and the treatments employed. The results are tabulated and discussed. 

 Strong Burgundy mixture applied about the middle of March gave good results, 

 later applications being ineffective. 



Comparative resistance of Prunus to crown g'all, C. O. Smith (Amer. Nat., 

 51 {1917), No. 601, pp. 47-60, figs. 6).— This is a more detailed account of the 

 work already noted (E. S. R., 36, p. 352). 



Winter injury of grapes, F. E. Gladwin {New York State Sta. Bid. iSS 

 {1917), pp. 107-139, pis. 8). — As a result of a study of light crops of grapes 

 during the years 1909 to 1916, the author was led to the conclusion that such 

 crops are due to injury to immature shoots by low temperatures. Embryo 

 flower clusters were found to be injured by low temperatures if they entered 

 the dormant period immature, yet the foliage of the bud might expand normally. 

 The effect of low temperatures following various periods when temperatures 

 rose high enough and continued for sufficient time to start activity is discussed. 



Experiments testing the effect of various fertilizer elements on maturity 

 indicate that neither nitrogen, phosphoric acid, nor potash influenced maturity, 

 and hence their effect was not apparent as influencing the degree of killing. 

 The extent of injury was observed to be closely correlated with poor drainage 

 of soils, although some killing occurred where drainage was reported as satis- 

 factory. Severe pruning after late frost injury in the spring is believed to 

 favor bud killing indirectly through inducing rank wood growth. Maturity of 

 bud and wood is probably correlated with the ripeness of the fruit, as deter- 

 mined from sugar analyses of the fresh juice. 



Resistance to low temperature is considered a species character and is 

 possibly correlated with hardness of wood. 



Why and when winter kills grapes, F. H. Hall {New York State Sta. Bui. 

 4SS, popular ed. {1917), pp. S-8, figs. 4). — A popular edition of the above, 



A fatal disease of mulberry, L. Montemaetini {Riv. Patol. Veg., 7 {1915), 

 No. 8-9, pp. 238-242). — The results to date of the inquiry regarding a disease of 

 mulberry (E. S. R., 33, p. 448) in seven Provinces have already shown it to be 



22397°— 17— No. 7 5 



