DISEASES OF PLANTS. 151 



the author to fruit ,<rro\vt'rs in hiH vicinity to ascertain the extent of the fliseaxe and 

 what means were taken to comljat it. Tlie results of iiis inquiry indicate that the 

 disease was rather widely spread and occasioned considerable lf«s. But little has 

 been done for its prevention in the region covered by the in(|uiry. Tiie author 

 recommends thorough spraying with Bordeaux mixture or other good fungicide, 

 ami gives foi-nudas for tlu'ir jireparation and dircctiDiis for tiieir ai)plication. 



The cause and cure of canker in apple and pear trees, P. Passv (Ganl. Ilinx. 

 22 [I'JOO), Xo. J1.J4, /'• -517). — The canker, which is said to be a serious disease affect- 

 ing the branches and stems of fruit trees, esi)ecially apj)le trees and sometimes pears, 

 is due tu Xirtrla (lilisshnd, the parasitic nature of which is fully estal)lislied. The 

 author states that different varieties of apples vary in their susceptibility, some l^eing 

 almost entirely unaffected by tlic disease; others, like Reinette du Canada, are 

 esi)ecially susceptible to it. By experimental inoculations, it was found possiljle to 

 produce the disease upon a variety of pear with conidial spores taken from another 

 pear tree. As means for the prevention of this disease, the author states the l)est 

 way is to burn all diseased branches. ^Vhere this can not l)e done, the cankers 

 should be cut out, removing every jjart attacked l)y the parasite, together with a 

 .portion of the sound wood, and treating the wood witii a strong antiseptic, such iia 

 Bordeaux mixture, iron sulphate, etc. 



The Monilia disease or twig- blight of apples and pears, H. MuivLEu-Tmnui.vu 

 {C'entbl. Bakt. a. Par., J. ML, 6 {WOO), No. 20, pp. 6'55-6'57).— According to the 

 author, during the past season, in May and June, there appeared in the orchards of 

 various parts of Switzerland a serious disease, in which the twigs of apple trees in 

 particular were attacked. There was observed to be some difference in the suscep- 

 tibility of different varieties, a few escaping serious injury. Shortly after blocjuiing, 

 here and there a twig was seen to wilt. As the disease progressed, others were 

 affected, until half or more of the newer twigs were affected. Examinations of the 

 diseased twigs showed that they were infested with a fungus which is determined 

 an Monillufructiyena. The sudden and unusual occurrence of this fungus is attrib- 

 uted partially to frost injuries, although the jiarasitism is established in a nuniber of 

 instances. As a means of prevention, it is recommended that all the diseased twigs 

 be cut back into the sound wood, and during the winter all material, such as leaves, 

 mummy fruits, etc., which carry the spores, should be collected and burned. 



Peach foliage and fungicides, W. C. Sturgis {ConiiecUcut State Sta. Rpt. lUOO, 

 pt. 3, pp. 219-254, pis. o). — On account of the serious injury whicli frequently follows 

 the use of fungicides on peach foliage, the author has conducted an extensive series 

 of experiments in which Bordeaux mixture of different strengths, soda-Bordeaux 

 mixture, ammoniacal copper carbonate solution, copper acetate, and potassium sul- 

 phid were tested. The amount of copper present in the Bordeaux mixture varied 

 from 1 to 5 lbs. to 50 gal. of water. The copper-acetate solutions were composed of 

 normal copper acetate as well as the subacetate. The result of spraying these differ- 

 ent nuxtures on the peach foliage are discussed at some length. Upon peadi trees 

 the use of Bordeaux mixture ccjntaining more than 2 lbs. of copper suljjhate to 50 

 gal. of water proved injurious to the foliage and to the fruit. Similar effects wete 

 observed when; the soda-Bordeaux mixture was used, some strengtiis of the solution 

 proving more injurious to the fruit than where the ordinary Bordeau.K mixture was 

 used. The ammoniacal c(jpper-carbonate solution ])roved injurious in tlie strengths 

 employed, and the subacetate of chopper caused serious defoliation of the trees. The 

 normal copper acetate, used in the same proportion as the subacetate, had only a 

 shghtly injurious effect upon the foliage. Potassium sulphid, at the rate of 1 oz. to 

 .'5 gal. of water, had no injurious effect upon either foliage or fruit. The author states 

 tliat the partial defoliation of well-grown 2)each trees by the application of fungicides 

 of medium strength late in the season may not l)e attended witii any serious or per- 

 manent injury, and in some cases a decided advantage may accrue in the earlier 



