DISEASES IN GREENHOUSE 123 



proper conditions in the house may entail 

 serious losses to the grower. 



ROOT KNOT OR EEL WORM 



Heterodera radicicola (Greef) M tiller 



Root Knot, {nematode galls) no less 

 important than Rhizoctonia and Fusarium 

 root rots, causes great loss to greenhouse 

 sweet peas. It does not, however, produce 

 a damping off in young seedlings. It 

 seems very probable, too, that root knot 

 in the case of the sweet pea opens the way 

 to the attacks of Rhizoctonia and several 

 other root troubles, producing also the 

 greatest amount of damage in light sandy 

 soils. 



Symptoms. The disease is character- 

 ized by swellings on the roots. These are 

 either small knots formed singly, in pairs, 

 or in strings, thus giving the affected root 



