January 1,.1910 
THE AUSTRALIAN GARDENER. 
“ Montefiore,” North Adelaide, Residence of Sir Samuel Way. 
Verrucosis. of Lemon and 
Other Citrus Trees. 
[By T., W. Kirk, F.LS. &., Lond., 
Government Biologist, in Leaflets for 
Gardeners and Fruitgrowers, No. 33, 
issued by the New Zealand Depart- 
ment of Agriculture. ] 
This disease is prevalent in America 
(principally in Florida), Japan, and 
Australia, It is not at all an uncommon 
thing to find lemons attacked by this 
fungus in boxes of fruit imported from 
the Commonwealih. On my visit to 
‘Queensland in 1898 I saw trees suffering © 
from vorrucosis, and since that date the 
‘disease has been steadily increasing in the 
Australian States. This diseaso has not 
‘as yet got a strong hold on the citzus 
_ orchards of the Dominion, but no steps 
‘should be neglected to eradicate it, as it 
is a very serious trouble. 
Verrucosis is caused. by certain micros- 
copic fungi belonging to the genus 
Cladosporium, which produce the warty 
swellings on fruit and leaf. The dis- 
figurement frequently becomes so great 
as to enormously depreciatethe value of 
the fruit, often rendering it unsaleable, 
besides dilibtating the trees by damaging 
the foliage, 
This disease is much worse in moist 
than in dry climates, hence California is 
practically free, although verrucosis has 
several*times been introduced, while in 
Florida the loss is estimated at over 
£12,000 per annum. Should it ever 
obtain a firm footing in the citrus 
orchards ‘of the northern portions of New 
Zealand, the humid climate will probably 
prove favorablo to its rapid spread. The 
disease having once been fouud, the 
importance of keeping a sharp look-out 
should need no urging. =~ 
_— Treatment. — 
‘Carefully remove and burn all affected 
fruits. 
with either Bordeaux mixture or ammon- 
iacal carbonate of copper. several times 
during the year. If the spraying is to be 
All the trees should be sprayed- 
done about the time of marketing of the 
oi the fruit the carbonate-of-copper wash — 
is preferable to the Bordeaux, but at 
‘other times the Bordeaux mixture is 
to be preferred, -as it is as effective and 
much oheaper than ammoniacal carbonate 
of copper. In moist seasons more 
_ sprayings will be necessary than in dry 
ones. 
The following are directions for making — 
Bordeaux mixture and ammoniacal car- 
bonate of copper :— ; 
Bordeaux Mixture (Summer Formula), 
_. Proportioris.—4lb sulphate copper, 4Ib 
fresh roche lime, 40 gallons water. 
Preparation.—Dissolve the 4lb  sul- 
phate of copper in 20 gallons water; slake 
the 4lb lime slowly, and make up to 20 
gallons: strain this milk of lime into the ~ 
solution of sulphate of copper, stirring 
briskly, 
Sulphate of copper may be dissolved 
by tying in a piece of sacking and sus- 
pending overnight just below the surface 
of the water, or by using hot waterg 
