1917] DISEASES OF PLAKTS. 51 



bitter pit in case of Grimes Golden, Jonatlmn, and otiicr varieties tlian medium 

 or light irrigation throughout the season. 



Blight-resistant roots — the first step toward, pear blight control, A. L. 

 WisKER (Mo. Bui. Com. Hort. Cal., 5 {1916), No. 2, pp. 1,8-53, fig. i).— Experi- 

 ence in California with pear blight (Bacillus aniylovorus) in the past two 

 years is said to have emphasized (he inability of orchardists alone to control 

 this disease. 



Comparisons are made as to adaptability for stocks of the French or wild 

 European pear (Pyrus communis) and the Japan or wild Asiatic pear (P. 

 sinensis). The latter is said to make the more vigorous growth, its seedlings 

 are less subject to leaf blight (Eniomosporium maculatum), its roots have 

 little tendency to sucker, and it resists blight better, on the average, than any 

 other root now in use. It makes vigorous growth with less soil moisture also 

 than does the French pear, and trees grown on Japan root suffer comparatively 

 little also from pear aphis. These and other claims are regarded, however, as 

 somewhat tentative. It is admitted that under conditions of excessive soil 

 saturation the Japan pear may be injured by root rot. 



Further studies on plum wilt, B. B. Higgins (Abs. in Phytopathology, 6 

 (1916), No. 1, pp. 117, 118). — In continuation of a previous report (E. S. R., 34, 

 p. 747), the author claims that the fungus causing the plum wilt is a general 

 wound parasite of woody plants but is not found occurring normally on any 

 plant outside of the genus Prunus. 



Summer sprays against American gooseberry mildew, B. T. P. Barker and 

 A. H. Lees (Jour. Bd. Ayr. [Lo7ulon], 22 (1916), No. 12, pp. 1 2 U- 1249). —The 

 authors, summarizing the work done by them during the past two years on 

 the summer treatment of American gooseberry mildew, state that their experi- 

 ence agrees with that of Eyre and Salmon (E. S. R., 35, p. 654), as regards the 

 injurious effects of fungicidal concentrations of liver of sulphur as previously 

 used in this connection. Trial has also been made of a combination not known 

 to have been previously tested, consisting of a mixture of liver of sulphur and 

 a soft soap and paraffin emulsion, which is said to have given the most promis- 

 ing results. How far the liver of sulphur furnishes the fungicidal factor is not 

 known, but it is thought that all the ingredients may be required for the full 

 effect. The primary object of this paper is to call this mixture to the attention 

 of other investigators. 



It was found that what are called hitting or contact sprays, designed to kill 

 the mycelium and conidia already on the bush, were rendered more or less in- 

 effective by the presence of air between the conidiophores and the conidia. In 

 a series of tests of protective or cover sprays, employing such fungicides as 

 Bordeaux mixture or lime sulphur, no entirely satisfactory results were ob- 

 tained, as the mildew reappeared, although in slight degree. The cost of treat- 

 ment and other details are discussed. 



[Fungus diseases of the cranberry], H. .T. Franklin (Massachusetts Sta. 

 Bui. 168 (1916), pp. 1-5). — A report is given of studies carried on on the fungus 

 diseases of cranberries, the v\'ork having been done in cooperation with the 

 Bureau of Plant Industry of this Department. 



Spraying experiments were conducted with Bordeaux mixture, and the re- 

 sults obtained are similar to those previously reported (E. S. R., 33, p. 350). 

 The sprayed plats yielded less fruit than the untreated checks, although the 

 keeping quality of the sprayed berries was somewhat better than the unsprayed 

 ones. However, berries from plats that had been treated in previous years 

 but not in 1915 showed poorer keeping quality than those which had not been 

 sprayed. 



