242 



THE PROTECTION OF WOODLANDS. 



Fig. 59. 



natural size. 



Young Beech stem can- 

 kered by Nectria 

 ditissima. 



natural size. 



Young Spruce damaged by 

 Nectria curcubitula. 



a. Sporophores hibernating 

 on the dead bark. 



held by the mycelium, 

 which perenniates so that 

 the disease goes on from 

 year to year, unless in- 

 fected twigs are cut and 

 burned (before spores 

 ripen, to prevent disease 

 spreading). 



The Canker of broad- 

 leaved trees, Nectria 

 ditissima (Fig. 59), chiefly 

 attacks Beech and Ash, 

 making Ash black in the 

 heart and useless, and 

 soon becoming epidemic 

 in Ash-groves, especially 

 on wet land. It" can be 

 distinguished from other 

 diseased conditions by 

 small dark-red globular 

 pustules. Growing only 

 parasitically, its spores 

 germinate on wounds 

 made by insects, frost, 

 hail, &c. , on young shoots 

 and poles, especially at 

 forks ; and the mycelium 

 lives chiefly in the bark, 

 killing infected portions 

 and gradually extending, 

 and canker-spots forming 

 as the dead parts cica- 

 trise, and gradually in- 

 crease till the pole or tree 

 is killed. Remedy. In- 

 fected saplings, poles, or 

 trees should be thinned 

 out without making 

 wound -surf aces by in- 



a. Clusters of red sporo- 

 phores, as seen dur- 

 ing winter months. -juring the bark on the poles or trees left standing. 

 6> ^aea'd Tod 8 .' Sh Wing The Coral-spot disease, Nectria cinnalarina, is 

 a common saprophyte on dead branches of broad- 

 leaved trees, and also parasitic on Horse-Chestnut, Lime, Maple, Syca- 

 more, and Elm, destroying the sapwood in rings and killing the parts 



