58 
FIRST ANNUAL REPORT OF TI1E 
now completely rotted, so that nothing remained of them hut a few short snags 
attached to the butt, and the first high wind that came would necessarily blow the 
tree over. On the dead and decayed roots of such trees, I found, of course, no Root- 
lice ; but Mr. Wright assured me that they were to be met with on the roots in great 
numbers in the summer, when the trees first began to droop and wither. Among the 
living roots on which I had found living Root-lice, there were a few roots as completely 
dead and rotten as those of the dead trees. 
At first I imagined that every tree must have been infected, when it was originally 
received from the nursery. But Mr. Carpenter subsequently informed me, that he had 
found the insect in abundance on the roots of seedling apple-trees, in the autumn 
following the spring when the seed was sown ; and another fruit-grower told me, that 
he had seen it on the roots of seedling apple-trees, when no other apple-trees were 
within 200 yards, and on land lately reclaimed from the forest. Clearly, therefore, the 
insect must pass from tree to tree, either in the winged form which Dr. Fitch found 
it to assume in October, in the State of New York, or by some of the wingless individ¬ 
uals, that inhabit the trunk or limbs, being blown to and fro by the winds through the 
instrumentality of the light, feathery down, which exudes from their bodies. Proba¬ 
bly the species lias always existed on the roots of certain forest-trees in this whole 
region of country; and when apple-orchards began to be planted, it emigrated onto 
the apple-trees. 
This rotting away of the roots, which, as it appears, had been noticed as long ago 
as 1858 by Mr. Dunlap, and attributed to its true cause, is popularly known in South 
Illinois as “rotten-root,” and was, at one time, considered as a mere natural decay, 
superinduced by the system of root-grafting now so very generally adopted in the 
West; while, as we have seen, Dr. Long, of Alton, attributed it to the operation of 
stagnant water on the roots.* The “Early Harvest” apple is said to be peculiarly 
subject to this mortal malady. Similar cases, where insects give the preference to one 
particular variety, or avoid one particular variety of a cultivated plant, are common 
in Economic Entomology. For example, the Colorado Potato-bug (Doryphora 10- 
lineata, Say) is known to avoid the Peach-blow Potato, and, as has been already shown, 
(above, page 21), the Rose-bug prefers the Clinton to all other grape-vines. 
But although the more southern parts of Illinois are far worse afflicted by this insect 
than the northern counties, yet it exists and does considerable damage even in North 
Illinois. Mr. Kinney, the Rock Island nurseryman, informs me,that he has often noticed 
a woolly louse, which can be nothing else but this species, on the roots of his young 
apple-trees, along with just such knots and swellings as it usually produces elsewhere ; 
and he has himself lost four or five bearing apple-trees, and knows of 20 or 25 others 
* Mr. Riley informs me that apple-trees, and more especially those that are young, sometimes die in 
South Illinois “ with their roots entire and discolored throughout from the surface-mark downwards,” 
but with “ no trace of any insect whatever ; ” and that this very distinct disease is “ known in the West 
and by Warder, Flagg and others as ‘Rotten-root.’” lain quite confident that the dead trees, with their 
roots almost entirely rotten, in Mr. Wright’s orchard were killed by the Root-louse; and the peculiar 
appearance which they presented has been already described, so that it can be recognized with facility. 
But I by no means wish to be understood as asserting, that every apple-tree that dies in South Illinois 
dies of the Root-louse. Perhaps, under the popular name of “ Rotten-root,” two very distinct affections 
of the roots of the Apple-tree have been confounded together, the one caused by the Root-louse, and the 
t other arising from unknown causes. I hope to investigate this question more fully during the coming 
season. 
