CHAP. XLII. ROSA‘CEH. PY‘RUS. 903 
the insects. The trunk and branches are liable, in some soils, and in moist 
situations, to be infested with lichens and moss, which must be scraped off ; 
and in others the mistletoe is apt to take root, which ought to be cut out. 
The American Bug, American Blight, Cotton Insect, or Woolly Aphis ( Aphis 
lanigera L., Eriosoma mali Leach), is one of the most common enemies of 
the apple tree, particularly in England. How it came to be named American 
blight is uncertain; the insect being found, in Britain, on crab trees, in plant- 
ations ; and, consequently, being, in all probability, indigenous. Insects of the 
allied genera A‘phis and Eriosoma attack various shrubs, and have been found 
on the leaves and roots of herbaceous plants. The A‘phis lanigera, when 
closely examined, resembles the kind of aphis, or plant-louse, which infests 
the rose, and other shrubs and plants; but, unlike the common plant-lice, it is 
clothed, or muffled up with a substance resembling cotton wool, in such 
quantities, that no one, who was not aware of the fact, would suppose it con- 
tained an insect. In very hot weather, portions of this woolly matter sepa- 
rate from the mass, and float about in the air; and are driven along by the 
wind, till they are caught by the branch of some other tree; and in this 
manner the insect is propagated. The following observations by a writer in 
the Entomological Magazine, under the signature of Rusticus, quoted in the 
Gardener's Magazine, vol. ix. p. 335., describe the mode of propagation of this 
insect, and give, also, a method of destroying it: —“ These blights wander 
wherever it pleases the wind to carry them ; and, if bad luck should drive one 
of them against the branch of an apple tree, there it will stick, creep into a 
crack in the bark, bring forthits young, and found a colony: the white cctton 
soon appears in large bunches; branch after branch becomes infected; the 
tree grows cankery, pines, and dies. How this is effected no one knows, 
though the cause and effect are too evident to escape the notice of the com- 
monest clown. In large orchards, it is vain to hope for a cure; but not so in 
gardens. Directly you see the least morsel of cotton, make up your mind to 
a little trouble, and you will get rid of it. In the first place, get a plasterer’s 
whitewashing brush; then get a large pot of double size; make your man heat 
it, till itis quite liquid; then go with him into the garden, and see that he paints 
over every patch of white, though not bigger than a sixpence ; the next morn- 
ing have the size-pot heated again, and have another hunt; and keep on doing 
so every morning for a fortnight. Your man will tell you it’s no use: tell 
him that’s your business, not his. Your neighbours will laugh at you for 
your pains: do it before they are up. I have tried it, and know it to be 
effectual. Spirit of tar has been used with partial effect ; so, also, has resin. 
Whitewashing has been often tried, and, as it contains some size, is not 
entirely useless; and some horticulturists think it ornamental: I do not.” 
Other Remedies for the Woolly Aphis. This insect, a writer in the Gardener’s 
Magazine, residing in Cornwall, observes, appears to be spreading continually 
into new districts, even where no new trees have been planted, more espe- 
cially in the bottoms of valleys. The acclivities of hills it ascends very 
slowly; and orchards in these situations are generally less affected by the 
insect than such as are in plains. The writer alluded to (Mr. Jonathan 
Couch, a scientific naturalist ) recommends diluted sulphuric acid as the agent 
of destruction. This.is formed, he says, by “ mixing slowly three quarters of 
an ounce of sulphuric acid with 74 oz. of water. In laying it on, care should 
be taken not to let it touch the clothes of the operator, in which it will make 
holes. It should be applied all over the bark by means of rags, the only parts 
exempted being the present year’s shoots, which it would destroy. It clears 
the tree of moss and lichens, as well as insects; and, if applied in showery 
weather, will be washed into every crevice in which they can harbour. The 
insects which are touched with it immediately die; and those that have not 
been touched with it very soon cease to yield so large a secretion of cotton ; 
by which means, if it be true that the young ones are conveyed by the winds, 
wrapped up in this mantle, their propagation must be curtailed. After the 
application of the acid, when the weather has been fair, I have seen them in 
