CONTENTS 



PAGE 



I. Concepts and terminology 3 



References cited 7 



II. Testing protective fungicides in the laboratory 8 



Development of the method 9 



Technic 10 



Important factors 12 



Clean glassware 12 



Standardization of the fungus and ot the conditions for spore germination. 13 



Source of spores 13 



Age of culture 14 



Kind of water 15 



Concentration of spore suspension and oxygen relations 16 



Temperature 18 



Light 19 



Time 19 



Application of the fungicide 19 



Recording results 21 



Summary 23 



References cited 23 



III. The solvent action of spore excretions and other agencies on protective copper 



fungicides 25 



Historical review 26 



Atmospheric agencies 26 



Suscept excretions 34 



Spore excretions 36 



Other hypotheses 42 



Experimental work 43 



Procedure 43 



The toxicity of copper 44 



The toxicity of calcium compounds 51 



The liberation of the copper from the protectant 53 



Atmospheric agencies 53 



The solubility of copper protectants in distilled water 53 



The solubility of copper protectants in distilled and rain water, 



under forced aeration 55 



Spore excretions 58 



The solvent action of filtrates from suspensions of germinating 



spores 58 



The action of spore excretions on bordeaux mixture in dialyzing 



sacs 62 



The sphere of influence of spore excretions 65 



Cumulative action 69 



The abstraction, by spores, of copper from large volumes of water 



flowing over copper protectants 69 



The rate of solution of soluble and " insoluble " copper com- 

 pounds 70 



The nature of the spore excretions 72 



Summary 73 



Bibliography 75 



