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_.