Mcculloch's cauliflower spot: signs 313 



where does the organism summer over? Can you obtain the 

 disease on the bleached flowering parts? 



Histology. — Fix in Carnoy's solution pieces of cauliflower 

 leaves and heads showing small spots, carry them through the 

 paraffin-infiltration process, section on the microtome, stain and 

 study. What are your conclusions regarding manner of infec- 



> 



r 



) * 



Fig. 237. — Flagella of Bacterium niaculicolum. Stained from a 2- day agar streak 

 by van Ermengem's method. X 1000. 



tion and process of tissue destruction? Is the disease ever 

 vascular? Is cellulose destroyed? 



Variability. — Nothing is known. 



Transmission. — Nothing is known 



LITERATUEE 



Read McCulloch: ''A Spot Disease of Cauliflower." Bul- 

 letin 225, Bureau of Plant Industry. Washington, D. C, 

 Government Printing Office, 1911. The organism is described 

 and named in this paper. 



