20 
conditions previously mentioned, and we 
have not found ourselves akle to distin- 
guish one from the other by the naked 
eye. Nevertheless, there is no possibility 
of confusion between them when examined 
under the microscope, more particularly 
if the, fungoid parasites, have been 
cultivated, and so encouraged to produce 
their spore-bearing organs Speaking 
generally, our experience has been’ that 
when the cultivated potatoes are affected 
with ‘dry’ and ‘wet rot’ the predominating 
growth vatied according as the conditions 
were dry or moist, If kept fairly dry, the 
Fusarium was found to gain the upper 
hand, and the tubers finally shrivelled 
into a hard dry mass, covered with a 
dense, rather short, white or pinkish 
mould-like growth, consisting of fungus 
filaments (hyphae), and bearing myriads 
of tiny, sickle-shaped, septate spores 
readily discernible under the low powef” 
of the microscope. Under moist con- 
ditions, bacterial growth was much more’ 
in, evidence, and caused the rapid 
putrefaction of the potato, the material of 
which became soft, slimy, dirty brown. or-- 
already 
black, foul. As 
mentioned, 
and . very 
thora that might have been present, and 
perhaps did so several times before we 
secured specimens in which the Blight 
became Tubers 
appeared to us favourable for this purpose 
showed in areas a rather loosely attached 
crumpled skin, a little sunken and dark 
coloured, which was very easily stripped, 
and immediately underneath this skin, a 
pronounced. 
brownish area dipping more or less into 
the potato, which is at this region usually 
softened and often of a faint bluish 
colour, but it is not. thought that this _ 
appearance is characteristic of Blight. 
Material from‘the affected area examined 
under the microscope-shows the peculiar 
hyphae of Phytophthora, and, if developed 
the characteristic fructification and 
lemon-shaped spores. These also can be 
readily seen with a low power of the 
microscope. Whilst Fit would serye no 
useful purpose to give in this place 
further details of the structure of this 
fungus, it may be’noted, as a matter of 
importance, that its hyphae penetrate in 
~ tunity occurs, 
tissue, 
either of , these conditions . 
could readily overwhelm any Phytoph- . 
which. 
THE AUSTRALIAN GARDENER. 
between the cells of the potato tuber, and 
live there ready to develope when oppor- 
The fungus is said to bea 
true parasite, and to feed upon the living 
However this may be, it appears 
to be able to remain dormant in potatoes 
fora time sufficiently long to enable 
infected tubers to be accepted and planted 
as healthy seed. This seems to have been 
the way in which the disease has been 
spread from place to place. On the other 
hand, when the disease attacks the foliage 
of the plant above ground it spores are 
thrust out from the small respiratory 
openings or stomata on the under side of 
the leaves, and then may be distributed 
about the field by wind currents. Under 
moist conditions the spores can then 
germinate wherever they are deposited on 
other plants, and 80 give rise. to fresh 
infections. Given suitable oppo:tunity 
for development the issue is devastation. ' 
At the present time it is impossible to 
say how long blight has been existent in 
Tasmania ; apparently local growers had 
no suspicion of its presence, so that it is 
either of recent introduction, or has been 
present under circumstances in which it 
does not exert the baneful effects recorded 
in Ireland and in New Zealand. The 
latter idea, while quite hypothetical, is 
certainly not an impossibility—Blight 
and climatic conditions seem to have been 
closely related. It may be that even if 
introduced into this State, it may not 
succeed in getting an epiphytic footing, 
There is some comfort in this hope, since 
this State has, no doubt, been exposed to 
the risk of its entry. In this disease, as 
in all others, there must be a stage when 
it is not recognisable to our unaided 
senses—one in which infected ‘potatoes 
could not have been noticed by the 
inspectors, and in that stage it may haye 
been introduced before before its ex- 
istence was discovered or even suspected 
in Tasmania or Queensland. The extra 
precautions which have been taken since 
its discovery in May lastafford a further 
measure of protection to this State, As 
already mentioned, the first samples of 
potatoes submitted were found to be 
affected with Fusarium and _bacilliary 
rots; these, being serious in themselves 
were, proclaimed under the + Vine and 
October 1, 1909 
Vegetation Diseases Act, 1901,’ on June: 
16 last, and thenceforth excluded ‘from. 
importation. No doubt this has helped 
to exclude also Phytophthora-in fected 
specimens. Nevertheless, it is very im- 
portant that growers, not only in the. 
State’s interests but their 
own, should keep a close watch upon. 
crops raised from Tasmanian stocks, and: 
immediately call the attention of the 
Department ‘to any mal-condition. 
thereof. ‘Treatment in the earliest stages- 
alone offers much likelihood of success. 
The measures to be adopted have already: 
also. in 
been dealt with in Mr. Butler's. 
article. We have only to add to them a 
suggestion with regard to potato: 
bags, which will be -rendered perfectly 
safe if they are boiled (truly boiled) for- 
at least ten minutes in water. 
—‘ Agricultural Gazette of N.S.W.” 
Show Fixtures. 
Oct. 
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Yorketown (Yorketown) ox A}: 
Belalie (Jamestown) «.. fag KE 
_ Penola (Penola) see 13 & 14 
Lake Albert (Meningie) ... ago ARE: 
Kingston (Kingston)... pene LOg 
Stanley (Clare) os terme 20s 
Strathalbyn (Strathalbyn) sy 
Secretaries of Shows are invited to- 
forward date of fixtures for insertion. 
S i 
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Oer FRBE BOOK on Insect Pests and Insecticides ts of great practical value. Send tor A. ‘ 
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