22 
The Oxchard. 
Black Spot in Oranges. 
This disease is one that is very pre- 
yalent in some of the orange orchards 
near Sydney. Like melanose, it lowers 
the market value of the fruit, It 
will be noticed that the round sunken 
_ Spots are large and conspicious, and 
seriously mer the appearance of the fruit. 
These pustules give rise to a multitude of 
spores (seeds) of the fungus, and as these 
spores germinate readily when they come 
in contact with the fruit, the disease 
spreads very rapidly; thus fruit that was 
perfectly clean and free from disease, as 
far as it was possible to see, during the 
month of August, or even September, was 
very badly diseased the latter part of 
October and through November. 
The disease does not appear to attack 
the fruit to any extenttill it is thoroughly 
ripe, when it spreads very rapidly, greatly 
disfiguring the fruit and rendering it more 
or less unsaleable; in fact, very badly in- 
fested fruit falls from the tree and is 
valueless. The disease spreads very 
rapidly amongst ripe fruit. As the disease 
apparently confines its attack to ripe 
fruit, the treatment that will probably be 
most efficacious will be spraying the fruit 
at intervals of ten days or two weeks at 
the time the fruis is most liable to attack 
—say from the middle of August to the 
end of September for the county of 
Cumberland—with a fungacide which 
will destroy the spores of the fungus; of 
if it does not actually destroy them, pre” 
vents their germinating. The bestremedy 
to use for this purpose will probably be 
THE AUSTRALIAN GARDENER. 
ammonia, carbonate of copper, prepared 
as follows:— 
— Directions for Making Ammonia- 
carbonate of Copper.— 
Formula: Copper Carbonate 
+ 5 0z. 
Ammonia (Liquor 
Ammoniz sp. gr.*880) 3 pts 
Water cee ++» 45 gay 
Make a paste in a wooden bucket of the 
carbonate of copper and alittle water. Add 
the ammonia, which will dissolve the 
paste, and then dilute to 
gallons. 
Copper carbonate is obtainable from 
wholesale chemists, but is not stocked in 
very large quantities, as there is little 
demand for it. The price is 1s. 9d. per 
lb., in 71b. lots. 
Owing to the difficulty of obtaining 
carbonate of copper in smaller towns, as 
well as the high price usually charged for 
it, the Department recommends that the 
fruit growers prepare it. 
forty-five 
The following is the method given by 
Pierce: — 
Py 
‘In a barrel dissolve 6 lb. of copper 
sulphate in 4 gallons of hot water. In a 
another wooden vessel dissolve 7 lb. of 
washing soda or sal-soda, in 2 gallons of 
hot water. The soda should be clear 
(translucent), and not white and powdery 
as it appears when air slaked. When cold 
pour the soda solution slowly into the 
copper solution. = As soon as bubbles 
cease to rise fill the barrel with water, stir 
thoroughly, and allow the mixture to 
stand over night to settle. The next day 
syphon off all the clear liquid from the 
top with a piece of hose, fill the barrel 
with water, stir thoroughly. and allow it 
to stand a second night. Syphon off the 
clear liquid the second day, fill the barrel 
with water, stir, and syphon off the clear 
liquid once more the third day. Now 
pour out the wet sediment from the 
barrel into a crock or other earthen 
dish, strain out the excess of water 
through a cloth, and dry slowly in an 
oven, stirring occasionally, if necessary, to 
overheating. Prepared in this manner 
there should be obtained, if none of the 
sediment in the barrel be lost, about 2.65 
lb. of copper carbonate.’ 
The cost of preparing carbonate of 
copper by this method will depend on the 
April 1, 1909 
cost of the sulphate of copper and the 
sodium carbonate (sal-soda or washing 
soda), The present price of copper 
sulphate is 3d. per lb., and washing soda 
2d. perlb.; thus the cost will be a® 
follows:— 
s. d 
6 lb. of Copper Sulphate, @ 3d. 1 6 
7 1b, of Sodium Carbonate (@ 2d. 1 2 
2 8 
As these ingredients will make 2:65 lb. of 
the carbonate of copper, the cost will be 
approximately 1s. per lb. 
The advantages of making it at the 
orchard are twofold; firstly, the sulphate 
is obtainable almost anywhere, thus 
saving delay, and secondly, the cost is 
less. 
Very little time is taken up, as there is 
no continuous stirring or watching as is 
the case with some mixtures, 
In addition to this spraying of the ripe 
fruit, it is advisable to give the trees a 
thoroughspraying with Bordeaux mixture 
as soon as the crop is gathered, as this 
spray will destroy loose numbers of spots 
that would remain on the trees till the 
next season. 
The following is the method of making 
this spray:— 
—Directions for preparing Bordeaux 
Mixture.— 
Formula: Copper Sulphate (blue- 
stone)  ... eT OmLDY 
Lime vee 41D. 
made up with 22 or 45 gallons of water, 
according to the season, the smaller pro- 
portion being the winter dressing. 
—Copper Solution,— 
It is immaterial whether hot cr cold 
water be used to dissolve the bluestone. 
If the mixture is to be made in a hurry, it 
is best to boil the copper sulphate in 
water. If there is plenty of time use cold 
water; but in this gase the bluestone must 
be suspended in a porous bag (bit of 
muslin or sacking) as near the surface of 
the water as possible. If the copper salt 
s thrown into the vessel, and water 
poured on the top of it, it will not dissolve 
in a week. When suspended as described 
it should dissolve in about twenty-four 
hours. 
The sulphate of copper solution when 
