Go out as soon as the sun is set with a lanthorn and a gallipot filled with strong brine, and visit each lily-shoot in succession. You will see the slugs congregated on your pets by hundreds, from the little tiny fellow of one-quarter of an inch long, who is eating your best lilies in order that he may grow into a larger and more capacious enemy, to the slimy monster of six inches long, who is attempting to fill his vast maw with lilies of great value. All are there, all devouring your best specimens, as though you were their most hated enemy—as indeed you will be if you want your garden to look gay. These slugs are not, as one would suppose, dirty feeders, but they are gourmands of the deepest dye. They are not content with the outside or decaying leaves—not they—they want the very tenderest tops of the young shoots! When the lilies are about a foot high, they will not eat the leaves at the base, they must needs crawl up the stem to feed on the tender growing top of the plants. But now you can have your revenge. Pick off with your fingers[2] every slug you can see, be he little or great, and put him into the brine. The brine kills and dissolves them in a very short time.
Some gardeners place cabbage-leaves, etc., on the ground as "traps" for slugs, but alas! the tender lily shoot is far more tickling to the palate of a slug than any cabbage-leaf!
The damage which slugs can do to lilies is incredible, and unless these pests are summarily dealt with, every lily in a garden may be decapitated ere the summer commences. One reason why lilies in pots do so well is that it is not so easy for the slug to get at them.
The lilies are singularly exempt from the ravages of animals other than slugs. The aphides or green flies are, however, often very troublesome. We will refer to this pest when talking of the treatment of lilies just before and during the flowering stage.
The leaves of some lilies are sometimes eaten by the larvæ of the Lily Beetle (Crioceris Merdigera), but as this insect is a great rarity in England, we will not describe it.
There is neither animal nor plant which is exempt from disease, and the lily has inherited this universal tendency to disease. There are not many common diseases of lilies, and very few even of these do much damage to more than one or two kinds. But some of these diseases give great trouble to the lily grower, and often tax his patience to the utmost.
Some lilies are very prone to a form of mildew which, beginning as a minute spot of discolouration on one leaf, eventually destroys the whole of the foliage and flower-buds, and turns a beautiful, well-grown, apparently healthy lily into a brown slimy stick.
This disease usually begins to show itself about the middle of May. A small grayish transparent spot appears on one leaf, and in about a month it has spread and completely destroyed the plant. Not all lilies suffer from this disease, and of those which are liable to be attacked, not all suffer to the same extent. Of all lilies, Lilium Candidum is the most frequently attacked, and in this lily the disease usually destroys the deciduous portion of the plant altogether. The other members of the Eulirion group of lilies: L. Brownii, Wallichianum, Washingtonianum, etc., are also frequently attacked, but are rarely much injured by it. It also occurs on L. Speciosum, L. Superbum, L. Canadense, and, indeed, most kinds of lily; but in these it rarely attacks the flower-head and does not, in our experience, do much harm. We have never seen the disease in L. Auratum, L. Tigrinum, or L. Longiflorum.
Of the cause of this calamity we know but little, but we rather think that it is often due to growing lilies in soils which are too poor or are exhausted. This, indeed, seems highly probable in the case of Lilium Candidum, the most frequently attacked of all lilies, for it is grown by most people without any care being given to it, and made to shift in a dry sandy garden exposed to the full blaze of the sun and scarcely ever watered. Where lilies can have a good rich soil, with plenty of water, the disease is very uncommon.
Once established, this disease is very difficult to cure. Syringing with solution of sulphuretted potash, or of sulphur boiled in lime water, will sometimes stop it, but too frequently the disease runs its course to the bitter end. If you uproot the plant and examine its bulb and root, you will find both quite healthy-looking.