INOCULATIONS WITH BACTERIA CAUSING PLANT DISEASE 297 



terial leaf spots. (4) Some varieties of plants are highly resistant to 

 pathogens which readily attack other varieties. Similarly, different 

 strains of bacteria often vary in pathogenicity. 



Table 29. Tentative Protocol for Plant Inoculations 



Host: Manner of inoculation: 



Variety Through soil 



History Through wounds 



Age By sprays 



Morphological condition Spreader used 



Stomata open By insects (name) 



Physiological condition Stage in life cycle 



Susceptibility Other means 



Environment Incubation : 



Treatment before Time 



Treatment after Environment : 



Pathogen: Temperature 



Strain Moisture 



History Light 



Culture on Intensity 



at °C Length of day 



for days Soil nutrients 



Inoculum used: Symptoms: 



Diseased tissue Location . . ; 



Entire culture Age of parts affected 



Bacteria : Severity 



Turbidity Description: 



Number per ml Early 



Filtrate Medium 



Products Final , 



Amount used per plant Effect on yield : 



Quantity 



Quality " 



INTERPRETATION OF RESULTS 



The results of research are valid only in accord with the reliability 

 of the methods employed and the accuracy of their interpretation. 

 After an experiment has been performed, it is insisted that a report of 

 such work must not be published for the use of others until repeated 

 determinations have been made and the results have been satisfactorily 

 analyzed. The simpler experiments are commonly performed with 

 suitable controls at least in duplicate or triplicate and carried through 

 three separate times. A good investigator does not become so enthu- 

 siastic about an experiment that he fails to view it impartially and to 

 accept sound evidence against it. On the contrary, he makes every 

 reasonable effort before publishing to find an error in the experiment 

 itself or in the conclusions drawn from it. 



