36 



Letters on the Diseases of Plants. 



the nature of the fungus that causes the disease, it has been carefully set 

 forth, more especially in drawings, in previous reports, to which I have had 

 little to add in recent letters excejjt that I have since seen much worse cases 

 on peach-trees than I had supposed possible. The injury on the peach-tree 

 seems, however, to be largely confined to the leaves. (See Fig. 47.) 



Remedies. 

 Spraying with ammonio-carbonate of copper, or weak Bordeaux mixture, 

 has proved a pronounced success w^herever it has been carefully tried. The 

 full details have already been published in this Journal, and they need not 

 be repeated here. (See Vol. Ill, p. 289.) 



5. The Crease in Peaches. 



I have noted a number of varieties of jjeaches, more especially late 

 varieties, which have a crease so deep as to be a decided defect. This deep 

 crease harbours both fungi and insects, whose ravages sooner or later cause 

 the peach to decay. This defect in peaches is as bad as the open channel 

 that exists in some varieties of apples, leading from the eye of the apple to 

 the core, and bad for precisely the same reason. 



VII. Gall-worm. 



Six years ago, when this Journal was first founded, I had the honor and 

 the sorrow to announce the presence in this Colony of the notorious gall- 

 worm Tylenclnis (or Heterodera) radicicola, 

 Greef., an insidious and destructive pest, in- 

 habiting the soil, and attacking the roots of a 

 great variety of plants, and causing damage in 

 many respects comparable with that produced by 

 phylloxera. Since that time I have found that 

 this worm occurs in at least all the Australian 

 colonies except Tasmania. Having examined 

 specimens from various parts of these Colonies, 

 I am in a position to say that it is on the high 

 road to occupancy of the whole continent. Its 

 ravages are so hidden from sight and of so 

 strange, and to the ordinary mind, of such in- 

 explicable a nature, that it is, beyond question, 

 already doing even greater harm than can be 

 demonstrated by evidence. But when I say 

 that I have collected, or received, specimens of 

 the disease from a chain of localities extending 

 from Bundaberg, in Queensland, to Adelaide, 

 South Australia, I think I am making a suffi- 

 ciently alarming statement. 



Inasmuch as the original article on this sub- 

 ject is now out of print, I think it best to insert 

 here a repetition of that part of the article that 

 deals with the measures that may be adopted to hinder the progress of the 

 disease. I am sorry to be unable to hold out any hope that the disease can 

 be anything more than hindered, which is the saddest statement I have to 

 make in all this long tale of disease and loss. Those who have their land 



Fig. 48.— Parsnip attacked and 

 deformed by root-galls. 



