THE 



VOL. 1. 



ST. LOmS, MO., JANUARY, 1869. 



NO. 



Cljt ^mmxiiit dBntanioIoigist. 



PUBLISHED MONTHLY BY 

 R. F. SXXJIDLE-2- &; CO., 



104 OlilVE STREET, ST. LOtns. 



TEKMS One dollar per annum iu ailvance. 



EDITORS : 



DEN.J. D. WALSn Rock Island, 111. 



CIL4.S. V. lULEY, 2130 Clark Ave St. Louis, Mo. 



THE APPLE-ROOT PLANT-LOUSE. 



(JSriosoma Ipemphigtt.i] pijri. Fitcli.) 



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For (he last twenti,- years a Wooly Plant-louse 

 has been known to infest the roots of the apple- 

 tree, causing thereon swellings and defoima- 

 tious of almost every pos.sible shape, and when 

 very numerous killing the tree. In the more 

 northerly parts of the Northern Stales this insect 

 is compai-atively rare, but iu southerly latitudes, 

 and especially in South Illinois, it is exceedingly 

 destructive iu apple orchards. We have our- 

 selves seeu as many as nine trees, all in one 

 square patch, that had apparently been killed 

 by it near Cobden, Ills.; and according to 

 Dr. Hull, "it is one of the worst enemies against 

 which our apple-trees have to contend, and is 

 much more common in our region than is gen- 

 erally supposed." {Ayr. Rep. J/o. Append., 

 p. 451.) As long ago as 1848 Mr. Fultou, of 

 Chester county, Pennsylvania, found this root- 

 louse and the knotty swellings produced by it 

 to be so abundant on nursery-trees in his neigh- 

 borhood, that thousands of young trees had to 

 be tlirown away, and it became difficult to sup- 

 ply the market. (Downing's Jlorticulturint, III, 

 p. 394.) And in August, 1858, ]M. L, Diinlap, 

 (Rural) stated in the Chicarjo Tribune, that in 

 an orchard near Alton •• the Wooly Aphis infests 

 tlie roots in immense numbers, and by sucking 

 up the sap destroys the trees, which iu its effect 

 has much the appearance of dry rot." 



It must not be supposed, however, that every 

 apple-tree that dies, without any appearance of 

 borers or other noxious insects working upon it 

 above ground, is killed by the Koot-louse. Dr. 



Hull has recently ascertained that healthy apple- 

 trees are sometimes destroyed by a fungoid 

 growth, of a white color and almost J inch tliick, 

 overspreading their roots. And we have our- 

 selves examined several trees in Macoupin Co., 

 III., which were perishing piecemeal, from some 

 unknown cause, without the least appearance of 

 any louse-work upon their roots. (See Amek. 

 Entom., I, p. 30.) In all such cases, it is toler- 

 ably easy to ascertain whether or not the lloot- 

 louse is the author of the mischief. Take a 

 spade and uncover the roots, either shortly 

 before or as soon as may be after the death of 

 the tree. If they are clubbed, knotted and dis- 

 torted to a considerable extent, as represented 

 at Fig. 70, a, and probably many oi them 

 rotten, we may know that this phenome- 

 non could only have been caused by lloot- 

 lice, and if there is no such fungoid growth 

 as was described above, we shall be pretty safe 

 ill bringing in a verdict of " Diedof Eoot-lice." 

 If, on the otlier hand, the roots are all of them 

 of their natural shape and size, we shall have to 

 look in some other direction for the origin of 

 the mischief. 



Although this insect usually contines itself to 

 the roots of the tree, yet a few may occasionally 

 be found on the suckers that spring up round 

 the but of tlic trunk, and even on the trunk and 

 limbs, especially iu places where a branch has 

 been formerly amputated, and nature is closing 

 up the old wound by a circle of new bark. 

 AVhere it works upon the naked trunk, it often 

 causes a mass of little granulations to sprout 

 out, about the size of cabbage-seeds, thus pro- 

 ducing on a small scale, the same elTects that it 

 does upon the roots. 'Wherever tlie insect works, 

 small as it is, it may be easily recognized by the 

 peculiar bluish-white cottony matter which it 

 secretes from its body, and wliich is never met 

 with in the case of the common Apple-tree 

 Plant-louse that inhabits tlie leaves and the tips 

 of the twigs. 



AVe have ourselves found winged Plant-lice, 

 very closely allied to our species, upon the twigs 

 of the Elm and the Ash in June, and upon the 

 lower side of the leaves of the lied Osier Dog- 

 wood in September; and Dr. Fitch has described 



