1 Dec., 1897.] QUEENSLAND AGRICULTURAL JOURNAL. 445 
DIsEAseEs. 
Collar rot is a disease of the bark at the neck of the tree, the cause of which I 
should not like to assert for certain. but hope to be enlightened on the matter by some 
of the gentlemen present at this Conference. 
I have found that, if the disease is detected in time, it can be stopped, and the 
tree will regain its health and vigour. I find that, to remove the affected part, to clean 
and paint it with olive and carbolic oils in equal parts, will, in almost every instance 
effect a cure; the difficulty is in discovering it in time. 
Generally, the first visible intimation of the disease is the fruit setting abnormally 
thick, and the foliage turning a sickly yellow colour. 
The true collar rot affects the tree from the neck upwards, while the roots below 
are perfectly sound, and will remain so for a long time after the tree is dead. 
Roor Ror. 
This disease is of a more deadly character, as it begins in the subsoil at the 
extremities of the roots, and proceeds upwards until the tree dies. Once a tree is 
affected, there is no cure. ‘Ihe cause of this disease is bad drainage and stagnant 
water, which poisons the roots ; or it may also be caused by some deleterious substance 
in the subsoil, such as salt, copper, antimony, or other poisonous minerals. Many 
people mistake it for collar rot, but they are totally different in their symptoms, and 
are brought on by totally different causes. 
Insect Pests, Scanz, &c. 
In my district, the lemon is infested by four different kinds of scale. These 
comprise, I believe, some of the worst of their species known up tothe present. At 
all events, if there are any worse, I hope I shall never have the misfortune to contend 
with them. The first is commonly known as the “Red Scale” of the orange and 
lemon (Aspidiotus coccineus), a native of Europe, immigrated or introduced to this 
beautiful continent for the especial annoyance, vexation, and loss of the Australian 
citrus-grower. There are very few places in Victoria or in any of the other Austral- 
asian colonies unaffected by this pest. 
Generally, the first indication of its presence is on the fruit, which it deteriorates 
in value, especially for table use. For peel-making it is not of so much consequence, 
as it leaves the skin while going through the pickling process, but it seriously damages 
the tree and in time kills it. ; 
Tam thankful that so far, I have succeeded in keeping this pest in check, and 
trees which, when I first discovered them to be badly affected by the scale, can now 
be looked over very carefully before finding a single specimen. 
No. 2 is the common Soft Brown Elongated Scale. This I believe to bea native of 
the colony, as I have seen it on native shrubs about the crecks. It is very prolific, and 
its worst feature is its very dirty habit of ejecting abdominally a drop of honeydew, 
which bursts into a spray when ejected and sprinkles the leaves, fruit, and wood of 
the tree, on which a black fungus grows, displeasing to the eye, very hurtful. to the 
tree, deteriorating the market value of the fruit, a necessitating washing to make 
them saleable. ‘This scale is easily kept under. 
No. 3 is Zcerya Purchasi, commonly known as the Cottony Cushion Scale, a 
native of Victoria, as I have often seen it on the native wattles in my district, and have 
found it on two occasions on lemon-trees, but only just started, so that it was easily 
exterminated. Its white colour makes it very easily distinguishable. This scale, 
which is said to have done so much damage in America, and which is so much dreaded 
in other countries, lives in my district within a few hundred yards of thousands of 
lemon and orange trees, and [ am thankful to be able to say it has only made two 
attempts to settle on them, and on each occasion was luckily detected at once. 
0. 4, Lecanium olee, or Olive Scale (called in America “Black Scale”), is the worst 
scale I have to contend with. It has been the cause of great trouble and expense to 
myself and others in my district. Once let it have a good start, and it will increase 
in countless thousands in one season, and will cover all the leaves and branches it 
attacks. It frequents apples, plums, peas, and quinces, but none so virulently as the 
orange and lemon. I have found that this scale distributes more honeydew than any 
other ] am acquainted with, and consequently it creates more black fungus. The 
leaves, branches, and fruit, in damp weather, become coated with the fungus, and if 
not checked, will so injure the trees that they cannot bear, and only just manage to 
live. The tops begins to die off, and in the course of a few years the tree gives up 
the fight. I have been a very close observer of this scale for this last couple of years, 
and find that they never stop hatching right through the winter. I have opened what 
I call the mother-scale, and always found some full of young in the running stage _ 
