CONTENTS. 



Page. 



Introduction ! 9 



Previous investigations ' 10 



The most serious diseases 12 



Blast _- 12 



Scald 13 



The fungus (Guignardia vaccinii Shear) causing blast and scald 14 



Pycnidial form 14 



Ascogenous form 15 



Cultures of Guignardia vaccinii 16 



Pycnidial form 16 



Ascogenous form 17 



Conditions or factors determining the production of the ascogenous 



form 19 



Dormant condition of the fungus 21 



Time and manner of infection 22 



Treatment 24 



Applications to the soil 24 



Improving the condition of the plants 24 



Selection of resistant varieties 25 



Application of fungicides 25 



Rot 26 



The fungus (Acanthorhynchus vaccinii Shear) causing the rot 27 



Ascogenous form 27 



Appressoria 27 



Relationship of the fungus 28 



Cultures of the fungus 29 



Treatment 30 



Anthracnose 30 



The fungus (Glomerella rufomaculans vaccinii Shear) causing an- 



thracnose 31 



Conidial form 31 



Ascogenous form 31 



Appressoria, or chlamydospores 32 



Cultures of Glomerella rufomaculans vaccinii 32 



Factors determining the production of the ascogenous fructifica- 

 tion 33 



Relationship of the fungus 33 



Dormant condition of the fungus 34 



Treatment 35 



Hypertrophy 35 



The fungus (Exobasidiwn oxycocci Rostr.) causing hypertrophy 36 



Relationship to other Exobasidii 36 



Treatment... , 37 



110 



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