482 QUEENSLAND AGRICULTURAL JOURNAL. [1 June, 1902. 
connected with an aerial growth. This fungus organisation is by no means. 
constantly existent; nor is its distribution when present co-extensive with 
injured surface of the fruit in connection with which it occurs. More than one 
distinct species of fungus apparently occurs under the conditions and in the 
connection named. 
On almost every orange exhibiting this second form of injury may be 
found dead examples of the previously mentioned plant-injuring Acarus or its 
eggs, and the above-mentioned features characteristic of it receive an adequate 
explanation in the manifestation of the peculiar feeding habit on the part of 
this animal; the fungus or fungi growing saprophytically on the dead resin- 
loaded tissue, and developing with greater or less prominence in response to the 
variations in meteorological features that from time to time obtain. 
Norr.—The same Acarus caused,/in the opinion of the writer, as already published, the Scab 
of the lemon. This he formerly attributed to afungus named Ramularia scabiosa n. sp. (‘ Insect 
and Fungus Pests,” p. 144, 1899), that was afterwards assigned to the genus Phyllosticta. This 
conclusion as to the origin of the obscure disease mentioned is now favoured by the Vegetable 
Pathologist of Victoria—Dr. McAlpine—as already announced (‘‘ Fungus Diseases of Citrus 
Trees,” p. 40-1). 
3. “ Maori” Disease, caused by: the orange mite (Phytopus oleivorus).— 
This is present only in a very mild form on- some of the oranges under 
examination, but seldom occurs in connection with them beyond an extent in 
which a mere lack of lustre is produced on the fruit whereon the mite that 
occasions the “ Maori” condition occurs. Accordingly the effects due to the 
attacks of the orange mite have not constituted those noticeable features on 
which Mr. Inspector Martin has based his condemnations of the consignments 
that are comprehended in the term ‘“‘ Melanose ” that he has used. 
Conelusion.—It will appear that, contrary to the suggested finding that 
the concluding paragraph of my previous letter mentioned as a matter for 
anticipation, the present report is evidence that the conclusions, so far as they 
relate to the state of the oranges in question, arrived at by the New South 
Wales authorities are sustained on sufficient grounds. . 
An important distinction, however, obtains between the views of my 
colleagues of the southern colonies and those of myself, in spite of this Bares 
ment. This relates to the causal agent of the malady. For whereas they deem 
this a parasitic fungus developing its spores externally; and the fruit victimised, 
to accordingly necessarily convey an infective element, whence it is a source of 
danger to horticultural interests, I on my part regard the malady as the result 
of the attacks of an Acarus: whence it follows that diseased fruit that still 
harbours this animal or its eggs, either endowed with life, should alone come 
under the provisions of the Diseases in Plants Acts of the different States that 
schedule “ Melanose”’ as a disease to be taken cognisance of. 
Recognising the disease to which this Report principally relates as a species 
‘of Acariasis, it has not previously occurred to me that it might be identical with 
one that, in New South Wales and Victoria, has. been ascribed by most com- 
petent authorities to a vegetable parasite. Indeed, until the exceptionally dry 
season, that would favour the development of such a malady as that under 
notice, was experienced, its presence was too little pronounced to justify 
rominent attention—a fact that would augur well with reference to the 
future degree of manifestation to be expected. 
T have, &c., 
HENRY TRYON, 
Entomologist and Vegetable Pathologist. 
P.S.—It has not been deemed necessary to refer to the so-called Melanose 
diseases of the citrus tribe met with in the United States and in Europe; with 
the latter, however, the Australian orange affection can have no connection.— 
H.T. 
The Under Secretary, Department of Agriculture, Brisbane. 
