PATHOLOGY OF YOUNG TREES AND SEEDLINGS. 233 



its presence. This species agrees with the Scottish speci- 

 mens in the form and size of its conidiophores and asco- 

 spores, and, although there are slight differences in the 

 minor characters of the two fungi, they resemble each other 

 so closely that the Scottish specimens may be provisionally 

 assigned to R. aquila. This species appears to produce a 

 rather less abundant development of hyphae in the tissues 

 of its host than is the case in R. quercina, and in this respect 

 approaches more closely to the condition found in the infected 

 spruce seedlings. 



The serious nature of the diseases caused by the species 

 of Rosellinia has been long recognised, and energetic measures 

 should be undertaken for their eradication. All diseased plants 

 should be burnt, and, in the case of trees, the roots should be 

 grubbed up as completely as possible and destroyed. If the 

 number of attacked plants is small, the diseased area should 

 be isolated by digging a trench round it ; this should be 

 1-2 feet deep and at least 9 inches wide, and care should be 

 taken to throw all excavated soil inside the area. This will 

 prevent the further spread of the fungus through the soil, but 

 measures must be also undertaken to kill the fungus in the 

 isolated area. Litter may be scattered over the surface and 

 burnt, or quicklime may be spread over the soil and then dug 

 in. Bare fallowing for several years in order to starve out 

 the fungus has also been recommended. It has been shown 

 that treatment with various fungicides, such as copper sulphate 

 (bluestone) and iron sulphate, will kill the mycelial strands in 

 the soil if applied in sufficient quantities, and, in dealing with 

 such serious diseases, the risk of poisoning the soil for a time 

 for all plant growth must be taken. The value of carbolic acid 

 as a fungicide for the strands of Rhizoctonia violacea in the 

 soil has been demonstrated by Salmon. ^ Forty gallons of 

 a solution of i oz. of carbolic acid to i gall, of water were 

 applied to a 19x9 feet plot of badly-diseased seakale ; the 

 resulting crop was practically free from the fungus and was 

 heavier and better in every way. 



As soon as the serious nature of the disease attacking the 

 spruce was realised, the destruction of all the diseased seedlings 

 and the thorough soaking of the seed-bed with copper sulphate 



1 " Disease of Seakale," Gardeners'' Chronicle, 4th July 190S. 

 VOL. XXXVI. PART II. Q 



