88 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
E February 4, 1892. 
about them to keep tbe temperature low, and of course these 
Orchids must never be dry at any time of the year. Keep the 
sphagnum growing, and the plants will thrive, provided the drainage 
is right. 
The best way to treat these Orchids is to three parts fill the 
pots with potsherds, placing a little charcoal to keep everything 
sweet and in good condition, then form a compost of half fibrous 
peat and half sphagnum moss ; chop both up together, but not too 
fine or small, take the plant and place it in tbe pot, keeping the 
plant 1 inch above the rim, placing the material carefully over the 
roots so that these are not injured. The best time to pot these 
Orchids is after they have flowered, but some gardeners differ on 
this point ; in my opinion, however, it is the best time. They do 
not all fl )wer at the same time, so must not all be potted at the 
same time. Nothing gives so much pleasure as watching Orchids 
opening at different times of the year, for with a moderate col¬ 
lection there are not many weeks in the year without some in 
flower. 
Orchids are much subject to yellow and black thrips, also to 
green and yellow flie®, and if they are not looked well after will soon 
disfigure the plants, and prove an eyesore for the rest of the year. 
The best way to prevent them is to keep the plants well under notice, 
and as soon as one insect is seen have the plant taken down and 
thoroughly washed with softsoap water, not too strong ; and in 
the case of thrips, after a thorough washing when the plants are 
dry use flowers of sulphur dusted very sparingly down the young 
growths. That I find is a preventive and worth being tried by 
every Orchid grower.—W. Cakr. 
Phal.®nopsis. 
Many of the early flowering species are now over, or soon will 
be, and those thit require potting should be attended to as soon as 
possible. Plants requiring fresh sphagnum should be seen to, 
taking care not to employ too much of it, as a mass of this moisture- 
retaining material may prove injurious. Where a shift is not 
required the old sphagnum may be carefully removed, and fresh 
living moss, well chopped, being worked carefully among the 
roots in its place ; crocks, well cleaned and broken fine, with or 
without sharp silver sand being mixed with it. All Orchids are 
partial to cleanliness, and none more so than Phalsenopsis. Any 
cleaning that may be required should be attended to at the time 
of potting, when the plants may be placed in their summer 
quarters. 
What the veteran cultivator, Mr. James Douglas, once said, 
respecting the excessive employment of sphagnum moss in 
potting Phalasnopsis may well be treasured up by those who 
grow or intend growing them — viz., “A mass of broken moss 
(sphagnum) in the centre of a pot or basket is always a source of 
danger,” This is no doubt true, much injury accruing from its 
excessive employment. Comparatively few roots are found in the 
potting compost, however small, the larger and healthier ones 
being as free as the air in which they delight.—W. R. W., 
Great Marlow, 
EXPERIMENTS IN TREATING THE POTATO 
DISEASE. 
(Continued from page 60.) 
Time of Applioation. —The Potato fungus does not usually 
attack the Potato crops before midsummer ; in fact, the fungus 
seems, from experiments that have been made, to require a mean 
temperature of 55° as a minimum, which occurs in this country 
about the third week in May ; but its vegetation is slow—that is 
it takes more heat or time to bring it into life than is necessary to 
continue its growth, once that becomes active. Thus we find the 
Potato disease virulent in la^e September and early October with 
no more heat than obtains early in May ; yet there is no disease, 
as a rule, until the eaily part of July. Potato disease does notenter 
glass structures until the germs outside are liberated by the warm 
weather ; then they come in through the ventilators. Still, if the 
cultivator may not have been careful to remove every particle of 
the preceding diseased plants and old soil, then disease may appear 
at an early date on Tomato plants, the germs springing from 
the soil. If we allow a mouth, say from May 18th, mean 
temperature 55°, to June 21st mean tempersture 61°, for the 
oosphere to produce a plentiful crop of conidia, there will 
be plenty of zo 'spores active in dewdrops and prepared to 
enter the Potato plants by the stomates early in July. That 
is the time to strike them with the Bordeaux mixture. The 
first yellow speck on the leaf of a Potato plant should be the 
signal to combat the enemy. Early crops that are to be lifted 
off the ground by mid-July will not need treatment;, but if 
they are to remain to mature apply the mixture directly a speck 
appears. We recommend the first treatment early in July, never 
later than the appearance of the first discoloured spot due to 
the fungus. Repeat in a fortnight, and continue the treatment 
at fortn)ghtly intervals, giving the last early in September. One 
treatment will be sufficient for the early crops, two for the second 
earlies, both being left to mature, and three generally for the 
latest crops, as the disease may not appear until August ; but if 
the disease appears so as to require five treatments by all means 
use them so as to stay the plague. Remember that success rests 
wholly in early treatment; the work is altogether preventive. 
Waiting untd the leaves become blackened before commencing the 
struggle can do no good as regards saving the tubers. The treat¬ 
ment has proved successful in France ; it hai routed the Potato 
fungus and every fungoid disease in America, and it has proved 
efficacious in this country wherever it has been applied thoroughly, 
and no evil effects have followed, but much good. Such, at least, 
is our experience of copper sulphate as a fungicide. 
ApPLYiNa THE Preventive— A question arises as to where 
the mixture is to be applied. The stomata are most abundant on the 
under side of the leaf or leaflets, but there are ample openings on 
the upper surface, the midribs, and the stems to let in enough 
germinal tubes to ruin the Potato crop ; and there are more stomata 
on the upper surface in wet weather—that.is, on leaves formed in 
wet weather, than in fine, and such are always worst infected, there¬ 
fore we say spray the whole plant and that will reach the fungus, 
evenly coating the plants with a thin film of the fnngicide. With 
the knapsack pump any intelligent labourer may spray the Potato 
plants in the rows at a fair walking pace, going one way of the row 
and taking the other in returning; thus the plants receive a full, 
but not overdose, on all the surfaces exposed to attack, and no 
fungus can push its germinal tube through the film without being 
destroyed. This is best done in dry weather, but wet or dry spray, 
for some of the mixture will remain from the first spraying until 
the crop is lifted. 
Mr. Jensen’s system is admirable Subject the seed tubers to 
dry heat, as before mentioned, and they will take “dry rot” or 
“ wet rot ” without delay. It will save gaps in the rows, introducing 
the disease in o the crop. Earth up the plants, it protects the 
tubers against infection by conidia washed into the soil, and the 
light admitted by drawing the tops aside lets daylight into other¬ 
wise crowded growth, checking exuberance, and assisting the crop 
to mature. The drawing aside is a check on exuberance, and 
tendency to form coarse waxy tubers. 
Then there is the cutting off or pulling up of the tops of 
diseased plants after the leaves are blackened and before the 
mycelium of the fungus has descended by the stalks and infested 
the tubers. That seems u-e'ess in Jensen’s view of tuber con¬ 
tamination, the contagion being by conidia washed into the soil, 
on or among the tubers ; but the top pulling is a part of the 
system, and we have found it first-rate, e'<pecially along with 
the deep moulding. Tbe tops can be cat off, or they can be 
palled up by placing the feet—one on each side of the plant in the 
same direction as the row. This plan saves the tubers to a great 
extent, but the produce is very much less than when the foliage 
is kept clean and healthy by the application of Bordeaux mixture, 
which insures the greatest weight of produce of the highest 
nutrient value, and it is the cheapest preventive, as it renders 
everything but good cultivation unnecessary. Kill the oospheres, 
and there will be no conidia ; destroy the conidia and zoospores, 
and there will not be any Potato disease. 
The Result op Treatment with Bordeaux Mixture.— 
One spraying when the plants are 12 to 15 inches high, another 
when brown specks appear on the leaves, and a third a fort¬ 
night later appear all that are necessary in ordinary seasons 
to protect the Potato crop from disease, for the mixture properly 
prepared—namely, with quicklime—adheres from first to last to 
the foliage, and the parts coated with the mixture are invulnerable. 
Plants treated in the manner described had no disease spots in 
1891 until August 10th, and those on parts—new growths—not 
dressed. These were given a film of the mixture, and the spots 
dried up. Early in September the growth was complete, and this 
allowed of the who e plant being coated with the mixture. The 
plants from first to last were graen and healthy, the haulm dying 
naturally. Result—no diseased tubers, and a full crop. 
Undressed p'ants were turning yellow and spotted, becoming 
curled in the leaflets, brown in the leaves, black in the stems and 
manifestly dying on August 10th. Early in September the un¬ 
treated plants were shedding their leaflets ; some leaves had 
collapsed, and at the end of that month the plants were brown 
and dry ; mere bare sticks. Result—two diseased tubers to one 
sound, and the whole crop two-thirds only of that of a full un- 
dieeased crop. More, the saleable tubers were practically nil, 
because the disease fastened on the “ fattest ” tubers. 
Sulphate of copper is largely used in the arts for making green 
