94 



MAINE STATE COLLEGE 



Fig. 2. Quince twig affected bj- Roestelia. a — Spore enlarged (origiual). 



Fig. 2, shows a quince twig affected by the fungus; Fig. 2, A, 

 one of its spores enlarged. 



The leaves of the specimens received were also affected by 

 another species of Gymnosporangium (Gr. lacerta) which had passed 

 its prime. Those of Eceslelia auranliaca, Peck, were in their prime 

 when received in July. 



Remedies. 



1. As this fungus is perennial upon cedar trees it could not be 

 killed by spraying with Bordeaux mixture. Possibly if sprayed at 

 the time the spores were ripening they might be killed and pre- 

 vented from being blown to quince and apple trees. This would 

 be practical only upon hedges and ornamental trees. It would not 

 be practical to spray forest trees. The rust stage of this disease 

 is an internal parasite and has done its worst work when the orange 

 patches and excrescences appear on quince and apple twigs, fruit 

 or leaves. It would do the quince or apple trees no good to spray 

 at that time. To spray early in spring when the spores from cedar 

 trees are floating in the air would suggest itself as a preventive 

 measure. To spray when the Roestelia spores are ripe would prob- 

 ably destroy them and prevent the infection of cedar trees. There 

 have been no spraying experiments tried with this disease so far 

 as we know. 



2. As the galls on cedar trees furnish the spores of this disease, 

 all cedar trees in the vicinity of the orchard should be destroyed 

 if possible. This would greatly lessen the chances of infection but 



