NEW ZEALAND WHITE ROOT-ROT 115 



on a stroma developed on the dead leaves, and are 

 characterised by the presence of radiating brown hairs 

 springing from their upper surface. 



The parasite is most abundant in damp situations and 

 where the trees are crowded. In dry, airy districts but 

 httle harm is experienced. 



Hartig, Alleg. Forst. und/agd., Zeit. Jan. 1884. 

 PrilHeux, Malad. des Flantes Agric, vol. ii. p. 208, figs. 



NEW ZEALAND WHITE ROOT-ROT 



{Rosellinia radtciperda, Massee.) 



This fungus is closely allied to the European white 

 root-rot {Rosellwia necatrix). Mr. Allan Wight of New 

 Zealand describes its ravages as follows : — ' This fungus, in 

 the mycelial stage, attacks a great variety of tree roots, 

 amongst the most conspicuous of which are the apple, pear, 

 peach, and all other common orchard trees. The white-thorn 

 is also very subject to its attacks, as well as a great many 

 Abies, and several of the native trees and plants. It also 

 attacks the cabbage, the potato, docks, sorrel, fern, and, 

 in fact, is almost omnivorous. Its movements are uncertain ; 

 sometimes a tree here and there dies, sometimes a whole 

 row, and very often acres are swept off.' 



The bark just underground, or the roots, are first attacked, 

 and presently a delicate white mycelium is seen on the 

 surface of diseased parts. This mycelium forms white 

 strands which run a few inches underground until another 

 victim is reached. As the disease progresses, numerous 



