I 



1918.1 DISEASES OF PLANTS. 551 



the foliage, while the latter may bui*n the fruit if applied freely in very hot 

 weather after July 1, though it favors high coloration and finish and vigorous 

 foliation. Lead arsenate is said to increase the fungicidal effectiveness of 

 lime-sulphur. Four applications are ordinarily required for primary apple- 

 scab infection, or more in a wet season, such as that of 1915. Late fall or 

 early spring plowing is recommended to reduce the infection. 



Spraying experiments in 1916 for the control of apple blotch, A. J. GUN- 

 DEBSON {Trans. III. Hort. Soc, n. ser., 50 (1916), pp. 248-251). — Reviewing pre- 

 vious work and conclusions by several investigators, the author notes briefly 

 the results of tests made at Flora, Clay County, 111., in 1916 against apple blotch 

 on 108 16-year-old Ben Davis trees, employing different fungicides. 



Bordeaux mixture (3:4:50) proved superior to lime-sulphur (2 J gal. to 100 

 gal. water) as regards protection, though it showed some russeting of the 

 fruit. Botli these sprays are regarded as valuable for protection if used three, 

 five, and seven weeks after the fall of the blooms. It is not advisable to alter- 

 nate these sprays. 



Points which were emphasized in the course of these observations were that 

 unpruned trees or trees with dense tops do not permit thorough spraying, that 

 low pres.sures are absolutely inadequate as regards apple blotch control, that 

 every part of the tree must be reached and covered, and that applications must 

 be made at the proper times in order to be .successful. 



Results of spraying experiments at the Neoga Station, Ciunberland 

 County, 1916, W. S. Brock {Trans. III. Hort. Soc, n. ser., 50 {1916), pp. 252- 

 273). — The spraying at Neoga, 111., during 1916 is said to have demonstrated 

 that a dust mixture should contain only active ingredients, of which from 80 

 to 90 per cent may be fungicidal, the rest insecticidal. Even distribution of dust 

 sprays requires exceeding fineness of materials, so that the dust will remain sus- 

 pended in the air as long as possible, enveloping the tree in a dense cloud. 



Liquid sprays are deemed superior to dust sprays as at present applied, 

 though the latter have some advantages in favored localities, their place being 

 rather that of a .supplemental application or a means of reaching the trees in 

 time where breakdowns or failure of water supply make liquid sprays unavail- 

 able. It may develop later from work to be done that certain applications, such 

 as the follow-up spray or that applied 10 days after blooming, should employ 

 the dust mixture. 



Figures are given on costs and on the relative effectiveness of sprays on in- 

 sects, scab, blotch, and sooty blotch. It is concluded that liquid sprays are 

 more efficient, they can be applied during high or shifting winds, they cost 

 less, and they can be used as dormant sprays; while dust sprays can be ap- 

 plied more quickly and require fewer men and teams. 



One season's experience with the dust spray, W. S. Perrine {Trans. III. 

 Hort. Soc, n. ser., 50 {1916), pp. 470-472). — It was found that a great saving 

 in equipment and time could be effected by substituting the dust for the liquid 

 form of spray. Almost perfect results were obtained with early apples, but 

 conditions and results were less favorable in case of late apples. A combina- 

 tion of liquid and dust gave very excellent results. Peaches on which dust alone 

 was used also showed decided benefit from the treatment. 



A bacterial disease of the Wragg cherry, W. G. Sackett {Jour. Bad., 2 

 {1917), No. 1, pp. 79, SO). — A disease observed by the author first in the sum- 

 mer of 1915 and kept under observation for further reports causes spots or 

 specks on cherries (which appear to start only before ripening), also on the 

 stems (the cherries sometimes dropping prematurely), leaves (causing a shot- 

 hole appearance), and young twigs (causing watery, elliptical, olive-brown dis- 



