A Conifer Disease. 



19 



there formed sclerotia embedded in the bark. At a later stage 

 these sclerotia rupture the cortex and appear at the surface 

 bearing a crop of spores (Fig. 3). This form of the disease is by 

 no means uncommon in this country but it does not appear 

 to have been recorded from abroad. 



In the first described form of disease, the spores, alighting on 

 the damp surface of quite young leaves or shoots, germinate 

 quickly and the germ-tubes pierce the delicate tissues at once. 

 In the second form of the disease, the germinating spores cannot 

 pierce the bark of a two-year-old seedling directly, but only as a 

 wound parasite, through minute wounds in the bark caused bv 

 late frosts, punctures of insects, &c. 



When the stem is attacked the plant invariably dies, as the 

 cambium is destroyed by the fungus, and the bark soon forms a 

 loose dead sheath surrounding the wood. When the leaves and 

 shoots are attacked the plant sometimes recovers, but is practi- 

 cally useless, as the leaders are destroyed, and a bushy stunted 

 plant is the result. 



It is quite certain that this disease, in one form or another, . 

 is much more abundant in our nurseries than is generally- 

 suspected. Many of the patches of dead plants in seed-beds^ 

 that are usually considered to have been killed by frost or other 

 unfavourable atmospheric conditions, have in reality succumbed 

 to the Botrytis, as has been proved by examination. 



This is more especially true in those instances where the 

 diseased patch gradually extends from a small starting-point. 

 In other instances the disease will travel along a single row of 

 seedlings for some distance, the closeness of the plants favouring 

 the rapid spread of the disease from one seedling to another, 



Preventive Measures. 



Perfect cleanliness in the seed-beds is of primary importance. 

 Weeds should not be hoed up and left to die on the ground in 

 the spring, when the leaves of seedlings are quite young, as the 

 Botrytis grows on all kinds of dying and dead plants, and the - 

 spores pass on to the leaves of the seedlings. 



In one instance the fungus causing the disease was found to 



C 2 



