HYACINTH BACTERIOSIS 339 



HYACINTH BACTERIOSIS 



{Bacterium hyacmthi, Wakker.) 



A destructive disease of hyacinths, well known in Holland, 

 attacks the bulbs in the resting condition, and also shows 

 itself in the foliage. The presence of the parasite is 

 indicated by the appearance of yellow spots on the bulb 

 or leaves, due to the presence of a yellow mucus teeming 

 with bacteria, located in the vessels and intercellular spaces 

 of the fundamental tissue. Infection of healthy plants with 

 this mucilage produces the disease. 



Wakker, Onderzoek der Zeikteji van Hyacinthen, Haarlem, 

 1884. 

 Prillieux, Malad. des Plantes Agric, vol. i. p. 22, fig. 



PINK BACTERIOSIS OF WHEAT 



{Micrococcus tritici, Prill.) 



Abacterial disease of grains of wheat, indicated externally 

 by a rose or purplish colour. The colour is brightest and 

 most pronounced in the superficial layer consisting of 

 proteids, less marked where starch predominates. 



The starch is first attacked, causing the grain to become 

 more or less hollow, afterwards the gluten, and finally the 

 cell-walls. 



The bacteria are globose or ovoid, depending on the phase 

 of development, and form a thin, opaque, colourless, nodu- 

 lose layer lining the cavity in diseased grains. 



This is interesting as being the first account of a bacterial 

 disease of cultivated plants causing real damage. 



Prillieux, A fin. des Sci. Nat. Bot., 6th ser., vol. viii., 1879 ; 

 and in Malad. des Plantes Agric, vol. i. p. 7, figs. 



