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 hyacinthi is a me- 

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

 motile by means of one long polar flagellum (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 th^ United States. 



It is very fortunate that there exists a considerable 

 difference of resistance to yellows among hyacinth 

 varieties, as seen by the following list : 



RESISTANT 



NON-RESISTANT 



Single Red 



Robert Steiger 



Gertrude 



Homerus 



Single Rose 



Charles Dickens 



Baroness v. Tuyll 

 Moreno 



Single White 



Grandeur a Merveille 

 La Franchise 



La Grandesse 

 La Neige 



Single Light Blue 



Captain Boyton 

 Czar Peter 

 Grand Lilas 

 Leonidas 

 Lord Derby 

 Lord Palmerston 

 Orandates 

 Queen of Blues 

 Schotel 



Grand Maitre 

 La Peyrouse 

 Regulus 



