268 Diseases of Greenhouse Crops 



help to complete the decay and the disorganization 

 of the bulb. Often bulbs are attacked on one side 

 only, in which case the growth of the foliage is also 

 one sided, curved, and bends over towards the dis- 

 eased side (fig. 57, b to h.). 



The Organism. Pseudomonas hyacintki is a me- 

 dium sized rod, rounded at both ends, and is actively 

 motile by means of one long polar fiagellum (fig. 

 57, i.). It is non-sporiferous, produces no gas, and 

 liquefies gelatin slowly. 



Control. It is fortunate that the disease has not 

 as yet proved serious in the United States. It is a 

 very important disease in the Netherlands, and its 

 introduction with imported bulbs should be guarded 

 against by growers in the United States. 



It is very fortunate that there exists a considerable 

 diflFerence of resistance to yellows among hyacinth 

 varieties, as seen by the following list: 



