H.191 DISEASES OF PLANTS. 749 



of that year. The results of this season's work are regarded as very 

 encouraging. 



It is considered Important to spray thoroughly, nt high pressure (above 210 

 lbs. per Bquare Inch), and precisely al the time required for each variety. 



Notes on the fruit blossom bacillus, < ). Gbove (I Hir. Bristol, Ann. lipt. Agr. 

 and Hmt. Research Sta., l'Jil. pp. 81-24).- The bacillus causing a serious dls- 

 ease affecting particularly pear blossoms and fruit spurs of pear trees was 

 Investigated In a series of experiments carried on during 1917 at the station 

 i<> ascertain whether it was sufficiently common in the soil to justify the 

 presumption thai tlie disease is carried by bisects from the soil to the plants. 



it appears that the organism is fairly common in the soil In April, but not 

 earlier, adhering to the roots of various plants which are mentioned, although 

 tests as to its effect upon the growth of some of these gave Inconclusive 

 results. The characters of this organism are said to correspond very closely 

 to those of the fruit blossom hacillus. 



Black spot and leaf curl, W. Laidlaw and C. C Bktttt.f.hank (Fruit World 

 Austral., I'.) (1918), No. !>. pp. 21^-211, figs. 10).— Tests with copper acetate 

 against peach leaf curl (Exoascus deformans) showed good results so far as 

 carried. Burpundy pave better results at 6:8:40 strength than did Bordeaux 

 mixture. The spray should be applied when the buds are in the pink stage. 



Black spot of apple due to Venturia incequalis appeared to he influenced more 

 by the time of spraying than by the fungicide employed, although lime-sulphur 

 pave better results than did Bordeaux mixture. The application should be 

 made when the central blooms of the cluster are fully open. 



Control of brown rot, J. W. CoiXABD {Jour. Agr. [New Zeal], 16 (WIS), No. 

 5. pp. 275-288, figs. 2). — A provisional account of studies looking to protection 

 against peach brown rot [Manilla fructigena) in the northern districts of New 

 Zealand after the severe attack of 1910-17 states that, while valuable infor- 

 mation has been pained, no definite course of treatment can yet be recom- 

 mended as reliable under adverse conditions. Intense attacks appear to be 

 due primarily to weather conditions, secondarily to soil and situation, and 

 thirdly to variety, though the softer peaches are not more susceptible, as was 

 formerly held. 



Tentative conclusions offered are to the effect that Bordeaux mixture at 

 2:3:50 as a summer spray is too strong for peaches, and any beneficial effects 

 are as yet undecided. Lime-sulphur and atomic sulphur caused more or less 

 leaf marking on all varieties. Soil dressings of iron sulphate at the rate of 

 1 and 2 lbs. per tree were made without appreciable effect. The need for 

 careful and judicious thinning of the fruit is indicated by the large per- 

 centape of infection at points where fruits are in contact. Destruction of all 

 affected fruits is regarded as essential, and all prunings should also be 

 destroyed. Further work is expected to lead to more definite conclusions. 



Plum diseases, L. Sox-rsac [Prog. Agr. ct Vit. (/.'''. FEst-Centre), .7.0 (191$), 

 No. 8, pp. 1S0-185). — Physiological diseases noted include court-non§, chlorosis, 

 asphyxiation (due to soil conditions), gummosis, and injuries due to bail and 

 other causes. Cryptogamlc diseases include root rot (Armillaria mellea, Anari- 

 eus melleus, Dematophora 7ircath.r, Rosellinia nrcatri.r), trunk and branch 

 rots (Polyporus fulvtis), mosses and lichens in moist situations, rust (Puecinia 

 pruni spinosw, Poly stigma rubrum), plum pockets (Exoa-scus pruni), spotting 

 [Fusicladium pruni), brown rot or gray rot [Monilia cinerea, (BtromaHnia) 

 cinerea), and crackinp (of doubtful causation). 



For cryptbgamic diseases of plum a treatment with Bordeaux mixture after 

 the appearance of the foliage in spring is considered as being generally safe, 



