Roses and Rose Growing Part 28

FOOTNOTES:

[7] Rivers' _Rose Amateur's Guide_.

[8] See p. 57.

CHAPTER X

ROSE PESTS

THE enemies of the rose are many. They are of two cla.s.ses; the insect foes, and diseases caused by Fungi. And their prevention and destruction are tasks, as every rose-grower knows only too well, which call for ceaseless vigilance and constant work, more especially in the early months of the season. For if remedies are applied in good time, the pests of both kinds give comparatively little trouble after May and June until the early autumn, when a fresh crop of both appears.

No such powerful weapon has ever before been put in the hand of the rose-grower, as the remarkable handbook on the _Enemies of the Rose_, published this spring (1908) by the National Rose Society. For here the veriest tyro can recognize the diseases which puzzle him and the insects which drive him to despair in all stages of their mischievous existence, figured in exquisitely drawn and coloured plates; while in the terse and admirable letter-press he is told how to combat their destructive ways.

This little book can be obtained by non-members of the Society for 2_s._ 6_d._, through any member; and it ought to find a place on the shelf of every rose lover.

=Mildew=, of all Fungoid diseases, is the worst we have to contend with.

Some roses, such as the lovely _H. T. Killarney_, the _Crimson Rambler_, the _H. P. Margaret d.i.c.kson_, and others, are specially subject to this pest; and unless measures are taken against it when the very first sign appears, it quickly spreads to other roses. Two seasons ago a plant of _Margaret d.i.c.kson_ had it badly in my garden, and infected its neighbour, _Frau Karl Druschki_, to an alarming extent.

This odious disease, though more or less always present in the garden, appears generally in marked strength twice in the season--first in spring, when the foliage is just fully developed, and secondly after the midsummer shoots are grown.

It must be attacked early before it gets any hold, in fact, before it actually shows, if we have reason to suspect its presence. _Flowers of Sulphur_ is the most usual and effective preventive. It is blown over the plants with bellows made specially for the purpose. Floating like a fine cloud all over the garden it settles on every part of the plant.

The early morning before the dew is gone is the time to apply it, as the evaporation of the dew has some subtle effect on the sulphur which greatly increases its efficacy. Rev. F. Page-Roberts strongly recommends _Black Sulphur_ instead of the ordinary yellow, used with one of the "Ideal" Powder Bellows, made by W. Wood & Son, Wood Green.

Another preventive, which is advised in the National Rose Society's handbook as extremely efficacious, is syringing with _Pota.s.sium Sulphide_, _Liver of Sulphur_--half an ounce to a gallon of water. The handbook advises adding a tablespoonful of liquid glue, or the whites of two eggs to every gallon of water, as this causes the solution to adhere better to the foliage. If thoroughly and carefully applied with a very fine syringe, such as the Abol Syringe, using the bend attached to get at the under-side of the leaves where the fungus first appears, this wash acts rapidly upon the pests.

_Mo-Effic_, a new preparation, has been highly recommended in the last two years. I have not tested it myself. But Mr. Mawley considers it most successful.

=Black Spot= is another troublesome pest. It attacks the foliage alone, and not only spoils the appearance of the leaves, but so injures them that they fall off prematurely. The disease can be best checked by spraying with the _Liver of Sulphur_ wash, beginning early in the spring and going on at intervals.

=Rose Rust= and =Rose Leaf Scorch= may also be combated with _Liver of Sulphur_ wash.

But in all these three last diseases, it is a matter of the greatest importance to collect the badly diseased leaves on the plant, and especially to pick up every one lying on the ground, and to see that they are burnt at once and not thrown on the rubbish heap, where they will only infect the soil.

=Sooty Mould=, the unsightly black stuff which often covers the foliage, is a parasitic fungus not upon the leaf itself but upon the "honey dew"

deposited by Green Fly. If therefore the honey dew is kept off by destroying the Aphides which secrete it, _Sooty Mould_ will not appear.

INSECT PESTS.

=Green Fly=, or =Rose Aphis=, is alas! too well known in every garden to need much description. But the reason why it is so difficult sometimes to get rid of this pest is not so commonly known. The Aphides breathe through pores at the sides of their bodies. And in order to kill them, some substance must be used which will close these pores. Therefore syringing with water or any clear liquid is absolutely useless; for if a few Green Fly are knocked off one shoot they will only settle on some other. We often hear people say after a thunderstorm, "This will clean the roses and wash off the Green Fly nicely." Far from it. They only increase the faster; while the caterpillars rejoice, and flaunt themselves openly on every bush. Then in despair some one uses paraffin or some violently caustic wash for spraying the Green Fly, and destroys his roses thereby.

Nature has mercifully provided some enemies to prey on the Green Fly--and these help in some small degree to keep the pest down. The chief of these is the Ladybird, which both in its adult and in its larval state devours them ceaselessly. The pretty green Lace-wing Fly or Aphis Lion is also useful, as its larvae are provided with "large sickle-shaped jaws for picking the Green Fly off the plants."

The Hover Fly--which looks like a small, slim two-winged bee or wasp--lays its eggs in the thick of a ma.s.s of Green Fly, and its green and grey leech-like maggots feed upon them. And the Ichneumon and Chalcid Flies lay their eggs in the bodies of the Aphides and their maggots feed on them from within.

But all these are of comparatively little help to the unhappy rosarian, who must therefore devise unnatural means to clear his plants.

As far as I know, with the exception of an Aphis brush--a useful invention, but one which needs very gentle handling--there are only two safe remedies for this universal plague. The usual one is a wash of soft-soap and qua.s.sia, in these proportions--

Best soft-soap 1 lb.

Qua.s.sia chips 2 lb.

Water 25 gallons.

Even this wash, excellent as it is, will sometimes fail to get rid of the scourge in a bad year. But I have found "Abol, White's Superior," a never-failing remedy. It is also much easier to use, as one only has to mix it with cold water according to the directions on each can, and it is ready in a minute.

If either of these remedies are used the moment the Green Fly appears, and the dose repeated a couple of days later in order to kill any that may have escaped the first spraying, we have very little more trouble until the second crop of Green Fly appears in September. It is well to syringe the plants thoroughly with pure water a few days after the second dose of either of these washes, as this knocks off the dead Aphides, and leaves the foliage clean and sweet.

Although paraffin in various forms is often recommended, let me urge upon my readers that it is a most dangerous substance to use upon the rose--a naturally delicate plant--as any remedy of a caustic nature is sure to do it far more harm than good.

Tobacco wash is recommended by the Continental rose-growers for Aphis, 1 part of tobacco-juice to 15 parts of water. If a little soft-soap is added it makes a better wash. This is also a good wash for

=Cuckoo Spit= or =Frog-Fly=.--This frothy substance if washed off will be found to contain a yellow creature, often closely wedged into the angle of leaf and shoot, or at the base of a flower bud. This is a "nymph" or young Frog-Fly--a most destructive insect--and unless removed it will so quickly suck the sap of the leaf and bud that it dies and falls off.

To get rid of them requires patience. We must either hand-pick the roses--or if we spray with the tobacco wash it is necessary to syringe the plant with plain water first, using some force, to wash off the white froth--and then spray with the tobacco wash to kill the "nymph."

This leads us to the more active and the worst of all the pests we have to fight against.

BEETLES, BEES, FLIES, AND MOTHS,

which either in their adult form or as maggots and caterpillars prey upon the rose.

Four Beetles are among the enemies of the rose. The beautiful green =Rose Beetle= or =Rose Chafer= does harm in both stages. As a grub it feeds underground on the roots; and as a beetle eats the foliage and the petals and anthers of the flowers. I find it is particularly fond of the delicate blossoms of the _Yellow Persian Briar_.

The =c.o.c.k Chafer= also eats the foliage, and its large white grubs devour the roots of the roses to such an extent that they often kill the plant. As the grubs remain for three years in the ground the damage they can do is incalculable; and they attack other plants besides roses.

Among the roots of a herbaceous Spiraea I lifted this last winter, I caught forty of these grubs, and found they had so honey-combed the roots that the plant had to be burnt.

The =Summer Chafer= and =Garden Chafer= also attack roses.

Where these four chafers are prevalent there is no cure but hand-picking. The beetles must be collected off the bushes; and the grubs carefully picked out of the roots, if we have reason to think they are present from the rose appearing unhealthy. Or they may be tempted out of the soil by placing gra.s.s turves upside down close to the plants, when they can be picked out and killed with a little boiling water.

The =Rose Leaf-cutting Bee= spoils the foliage by cutting semi-circular pieces out of the leaves to line its nest. A few years ago I found that a fine young plant of _Tea Rambler_ was so relished by this bee that hardly a leaf was left intact. There is no cure but to watch the bee going into her nest and there to destroy it after dusk.

Of all pests that the rose-grower has to fight against

CATERPILLARS AND MAGGOTS

are the very worst. For there is no real remedy against their endless and varied depredations save hand-picking; or as some one has tersely put it, "just a little gentle washing with non-caustic substances, and just a lot of finger-and-thumb work." This is tedious, and often disgusting; but it is the only way.

These loathsome pests are the larvae of certain flies and many kinds of moths.