Parasitic Attack un " Eucalyptus Globulus.' .s5;j 



spread to living tissues, either by means of the mycelium invading new 

 shoots directly from the infected stumps or by dissemination of the 

 spores of the fungus which are produced in immense quantities by the 

 sporophores, and which through the agency of wind and rain, on 

 finding suitable lodgment in any wounds that may be present, germi- 

 nate and set up new infections. 



The above conditions were observed in the two blocks of nearly 

 pure E. globulus. Immediate felling of these blocks was recom- 

 mended, to be followed by piling and burning all debris of leaves and 

 branches on top of the infected stumps to destroy the sporophores and 

 thus prevent infection spreading by means of the spores to the adjoin- 

 ing block Painting stumps with carbolineum or tar was also 

 suggested as an alternative preventive measure. 



The recommendations were carried out, and on inspecting the two 

 blocks, in June, 1920, a crop of coppice growth l)ad again sprung up, 

 and of fairly normal appearance, except for a somewhat dingy colour, 

 from 2 to T feet in height. 



The stumps were again covered with an abundance of fruiting- 

 bodies, showing that the bxirning process had only a temporary effect 

 and did not destroy the fungus inside the stumps. The young coppice 

 shoots growing from diseased stumps showed light brown discoloured 

 streaks on the bark directly adjoining the stump. Examination of 

 these revealed the fact that the discoloration penetrated as far as the 

 cambium and as traces of mycelium were found in this area it was 

 concluded that this discoloration was probably due to the fungus 

 spreading from the stump into the new shoot. 



In a corner of one block some trees had apparently been cut after 

 the felling and burning of the main portion, the 'inner wood of the 

 stumps of which also disclosed a light brown discoloration and the 

 soft dry rot characteristic of the action of the fungus. (Plate II.) 



Although the fungus had attacked dead wood in the stumps of all 

 species, a careful search failed to discover it on the living tissue of 

 anj' other species than E. globuhts, either on young shoots or live 

 stumps. 



In the third block the various species are more or less confined to 

 pure groups with only a small percentage of E. globulus. Felling was 

 here only recently begun and so far confined to E. rostrata. 



Here again there was no sign of the fungus on living tissue 

 except on E. globulus. Practically every tree of this species was, 

 however, badly attacked, the lower part of the stems being generously 

 covered with fruiting bodies to a height of several feet, while the 

 cambium of young shoots was jienetrated by the mycelium. 



The Willows. 



Local conditions in this situation differ very slightly from those 

 at Cliffendale. It is ten miles east of Pretoria, in a wide open valley, 

 at an elevation of about 4500 feet with a north aspect and A^ery gentle 

 slope. The soil is here also of a sandy nature, but the shale is more 

 pronounced and nearer the surface. The rainfall which averages 

 28. oG inches is probably a couple of inches less than at Cliffendale. 

 The principal species in the area, where the fungus was found, are 

 E. resinifera, E. rostrata, E. tereticornis, and E. sidetoxyloiri. 

 E. globulus is confined to an avenue and a few scattered specimens. 



