cox TH NTS. 



i-ngo. 



Introduction ~ 



Tlie disease and its (;aiise ^ 



The diseaseil spots on the apple f^ 



The l)itter-rot fungus 9 



The mycelium 9 



Summer spores I^^ 



Ascospores 1*^ 



Germination of the spores 10 



Bitter-rot i-ankers on the l)ranches H 



Source of infection and spread of the disrast' 11 



Intiuencing conditions 12 



Weather 12 



Moisture 1'^ 



Temperature l-^ 



SusceptibiHty of different Aarieties 14 



Remedial measures 15 



The Virginia experiments 1" 



The experimental trees 18 



The plan of the experiment - - 1^ 



Object 19 



Spraying scheme 19 



Weather conditions attending the experiment 20 



Results - 21 



Beneficial effei-ts of spraying 25 



Effect of the treatment on other diseases 26 



Scab 26 



Leaf-spot 27 



Sooty-blotch 27 



Injurious effects of the treatment 27 



Russeting ~< 



Coating of Bordeaux mixture ■ 28 



Commercial ojjerations 28 



Results in several orchards 28 



Preparation of Bordeaux mixture 31 



Method of applying Bordeaux mixture 32 



Conclusions and recommendations 32 



Description of plates - 36 



5 



