330' 



THE FARMERS' REGISTER. 



are used in the making of ink. The lice which 

 inhabit or produce them, generally ditier Crom the 

 others, in havina; shorter antennae, being without 

 honey-tubes, and in frequently being clothed with 

 a kind of white down, which, however, disap- 

 pears when the insects become winged. 



These downy plant-lice are now placed in the 

 genus Eriosoma, which means woolly body, and 

 the most destructive species belonging to it was 

 first described under the name of jfphis lanigera, 

 by Mr Hausmann. in the year 1601, as iniesiing 

 the apple trees in Germany, It seems that it had 

 been noticed in England as early as the year 1787, 

 and has since acquired there the name of American 

 blight, from the erroneous supposition that it had 

 been imported from this country. It was known, 

 however, to the French gardeners for a long time 

 previous to both of the above dates, and, according 

 to Mr Renie, is found in the orchards, about Har- 

 fleur, in Normandy, and is very destructive to the 

 apple trees in the department of Calvados. There 

 is now good reason to believe that the mifcalled 

 American blight is not indigenous to this country, 

 and that it has been introduced here with fruit 

 trees from Europe. Some persons, indeed, have 

 supposed that it was not to be (bund in this coun- 

 try, at all, but the late MrBuel has stated that it 

 existed on his apple trees, and I have once or 

 twice seen it on apple trees in Massachusetts, 

 where, however, it stills appears to be rare, and 

 consequently I have not been able to examine the 

 insects sufficiently myself. The best accotjnt that 

 I have seen of them is contained in Knapp's 

 Journal of a Naturalist," from which, and from 

 Hausmann's description, the following observa- 

 tions are chiefly extracted. 



The eggs of the woolly apple tree louse are so 

 email as not to be distinguished without a micro- 

 scope, and are enveloped in a cotton-like substance 

 furnished by the body of the insect. They are de- 

 posited in the crotches of the branches and in the 

 chinks of the bark at or near the surface of the 

 ground, especially if there are suckers springing 

 from the same place. The young, when first 

 hatched, are covered with a very short and fine 

 down, and appear in the spring of the year like 

 little speclvs of mould on the trees. As the season 

 advances, and the insect increases in size, its 

 downy coat becomes more distinct, and grows in 

 length daily. This down is very easily removed, 

 adheres to the fingers when it is touched, and 

 seems to issue from all the pores of the skin of the 

 abdomen. When fully grown, the insects of the 

 first brood are one tenth of an inch in length, and 

 when the down is rubbed off', the head, antenna), 

 sucker, and shins are found to be of a blackisfi 

 color, and the abdomen honey-yellow. The young 

 are produced alive during the summer, are buried 

 in masses of the down, and derive their nourish- 

 ment from the sap of the bark and of the alburnum 

 or young wood immediately under the bark. The 

 adult insects never acquire wings, at least such is 

 the testimony both of Hausmann and Knapp, and 

 are destitute of honey-tubes, but from time to time 

 emit drops of a sticky fluid from the extremity of 

 the body. These insects, though destitute of 

 wings, are cq^eyed from tree to tree by means of 

 their long down, which is so plentiful and so light 

 as easily to be wafted by the winds of autumn, and 

 thus the evil will gradually spread throughout an 

 extensive orchard. The numerous punctures ol 



these lice produce on the tender shoots a cellular 

 appearance, and wherever a colony of them is es- 

 tablished, warts or excresences arise on the bark ; 

 the limbs thus attacked become sickly, the leaves 

 turn yellow and drop off; and, as the iniection 

 spreads (rom limb lolimb, the whole tree becoraea 

 diseased, and eventually perishes. In Gloucester- 

 shire, Enaland, so many apple trees were destroyed 

 by these lice in the year 1810, that it was feared 

 the making of eider must be abandoned. In the 

 north of England the apple trees are greatly in- 

 jured, and some annually destroyed by them, and 

 in the year 1826, they abounded there in such in- 

 credible luxuriance, that many trees seemed, at a 

 short distance, as if they had been whitewashed. 

 Mr. Knapp thinks that remedies can prove 

 effipacious in removing this evil only upon a small 

 scale, and that when the injury has existed for 

 some time, and extended its influence over the 

 parts of a larjie tree, it will lake its course, and 

 the tree will die. He says that he has removed 

 this blight from young trees, and from recently 

 attacked places in those more advanced, by paint- 

 ing over every node or infected part of the tree 

 with a composition consisting of three ounces of 

 melted resin mixed with the same quantity offish 

 oil, which is to be put on while warm., with a 

 .painter's brush. 



Sir Jose[)h Banks succeeded in extirpating 

 the insects from his own trees by removing all 

 the old and rugged bark, and scrubbing the trunk 

 and branches with a hard brush. The application 

 of the spirits of tar, of spirits of turpentine, of oil, 

 urine, and of soit soap, has been recommended. 

 Mr Buel found that oil sufficed to drive the insects 

 from the trunks and branches, but that it could not 

 be applied to the roots, where he stated numbers 

 of the insects harbored. 



The following treatment I am inclined to think 

 will prove as successful as any which has hereto- 

 fore been recommended. Scrape ott all the rough 

 bark of the in'ected trees and make them perfectly 

 clean and smooth early in the spring ; then rub 

 the trunk and limbs with a stiff brush wet with a 

 solution of potash, as hereafter recommended for 

 the destruction of bark lice ; after which remove 

 the sods and earth around the bottom of the trunk, 

 and with the scraper, brush and alkaline liquor, 

 cleanse that part as far as the roots can conve- 

 niently be uncovered. The earth and sods should 

 immediately he carried away, fresh loam should be 

 placed around the roots, and all cracks and wounds 

 should be filled with grafting cement or clay mor- 

 tar. Small limbs and extremities of branches, if 

 inlected, and beyond reach of the applications, 

 should be cut off and burned. 



There are several other species o[ Eriosoma or 

 downy lice in this stale, inhabiting various forest 

 and ornamental trees, some of which may also 

 have been introduced from abroad. The descrip- 

 tions of foreign plant-lice are mostly so brief and 

 imperfect that it is impossible to ascertain from 

 them which of our species are identical with those 

 of Europe ; I shall therefore omit any further 

 account of these insects, and close this part of the 

 subject with a lew remarks on the remedies to be 

 employed for their destruction generally, and some 

 notice of the natural enemies of plant-lice. 



Solutions of soap, or a mixture of soap-suds and 

 tobacco- water, used warm, and applied with a wa- 

 tering pot or with a garden engine, may be env- 



