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Oak (Kermes is the insect)

Kermes is the insect which yields a scarlet dye nearly equal to cochineal, and is the "scarlet" mentioned in Scripture; it feeds on Q. coccifera, an Oak from Asia Minor, &c. The acorn cups of Q. AEgilops are largely imported from the Levant for the purposes of tanning, dyeing, and making ink. The Oak Galls of commerce are yielded by Quercus infectoria, also a native of the Levant; these are much more rich in tannin than those produced in this country. See also Quercus.

Insect Pests. The number of these is legion. In Kaltenbach's "Pflanzenfeinde," there are 537 species of German insects recorded as living, more or less, on Oaks, and the number might be largely increased were the compilation continued up to the present date. Many of them, it is true, live habitually upon other trees, and on shrubs, only occasionally attacking Oaks, and seldom doing very great harm to the latter; yet even they may at times do great damage to Oaks, such as the larvae of various moths (see Hybernia, Lackey Moth, Liparis, Orgyia antiqua, &c.) to the leaves; Cockchafer grubs, Mole Crickets, &c., to the roots; Balaninus nucum, or Nut-Weevil, in the fruit, &c. It may, indeed, be said that no part of the tree is safe from the attacks of insect foes; but it is impossible here to do more than mention a few of the more interesting and important of these. Several beetles (see Tomicidae), e.g., Platypus cylindrus, Xyleborus dryographus, &c., and some moths (see Goat Moth) bore into the wood, and render it unfit for use; but, fortunately, they seldom attack healthy trees. As a precaution against them, all the dead trunks should be removed, and dead branches should be destroyed. The other moths above mentioned are hurtful by consuming the leaves of Oaks, Beech, and many other trees. But even more thorough in the extent of its ravages is a small moth (Tortrix viridana), which almost restricts itself to the common Oak. It reaches about 4/5in. in the spread of the front wings, which are green. The larvae live for a time in the buds, then in the leaves, and pupate in leaves spun together, or in the soil. In some seasons, and in certain localities, hardly a leaf is allowed to remain on the trees. Shaking the branches over sheets laid on the ground will cause the larvae of all the moths to fall on to the latter, from which they may be swept up and destroyed. The same method may be employed for the capture of various kinds of small beetles, chiefly Weevils, that gnaw the leaves and buds, as well as of Cockchafers, which, at times, do considerable damage to the trees.

The leaves are frequently mined by the larvae of small moths and beetles, but the injury from this cause is too slight to call for discussion at present; and, for the same reason, the larvae that feed in the buds may be passed over in silence. Among the more frequent causes of injury to the acorns is the beetle Balaninus nucum (see Nut-Weevil). Numerous species of Green Fly attack the Oak, and, at times, must weaken the trees very greatly, covering the lower leaves with honeydew, among which grows the Fungus Capnodium quercinum (see Oak Fungi), which may, in some cases, prove hurtful to the trees. But, of all the insects that attack Oaks, probably the most striking, in respect to the effects produced by them, are the makers of the various Galls so frequent and so noticeable on Oak trees. See Oak Galls.