The Indianapolis journal. [volume] (Indianapolis [Ind.]) 1867-1904, 1884-06-07

yard that comfortably supports eghty-one
species of insects eight on its roots, fourteen on
its branches, fifty on its leaves and nine on its
fruit, Is, to say the least convenient An inter-
esting description, not only OF each OF these IN
sects but also of their enemies can be found in
a recent book, Saunders's Insects Injurious to
Trees. This book will be found highly useful
from the fact that at the end of each description
of an insect the best known remedy against its
ravages is added.
The class lCoceidael to which two of the in
sects found on the apple-tree belong, has been
carefully studied by j. II. Comstock, and the re-
suits Of his Investigations, together with numer
Gus Illustrative plates, have been published in
the report for 1880 of the United States Agricul-
tural Department Leaving out of account the
rest of this excellent report, his work alone
would be sufficient to entitle this book to place
among the most valuable scientific works Of the
day
The first of these, the oyster-shell bark-liee,
are very pernicious insects, brought over from
Europe some eight years ago. Their scales are
about one sixth of an inch long of brownish
color, and shaped like the shell of
TN oyster. They adhere to the bark of
the tree, and are sometimes so numerous as TO
almost cover the branches. Each of these scales
covers from fifteen to hundred eggs, which
hatch early in June The lice leave their scales
after few days and wander over the tree to
find suitable place for attaching themselves
They select the newer growths, where they can
easily obtain sap to live upon. They insert their
small hut very sharp beaks into the wood and
extract the sap. Delicate threads exude from
their bodies a little later and these gradually
harden into a scally covering. BY the last of
August the female louise has become bag OF
eggs. The parent dies. these eggs hatch the
following spring, and the same process is re-
peated.
The seurvy bark-lou is a native insect, which,
in general way has the same characteristics.
The veterinary surgeon is now prominent
figure in an agricultural college, but his honorS
are to be divided. The plant doctor is the com
TTlfrT In eafa Of he diaDfT no.
tween Professors Riley and Comstonk in regard
to the best method of destroying bark-lice. it
does seem as if plant doctor was really needed
to look after the interests of the plant In
fiuenced as the eHtOmolcgist may be by the
public, which is willing TO support him, as com
pensation for helping it to get rid of parasitic
insects, he must still take secret pleasure IN the
insects success. Only one who cares more for the
plant than for the insect can really look after
the interests OF the former. Fortunately no one
will be kept from following the vocation Of
plant doctor for want Of proper facilities for
study. The old apple-tree III the back yard is q
hospital equal to any in Europe Moreover, the
study of the art Of healing plants is not nearly
as difficult the study of the art of healing ami
mails. The plants simple organism make those
complicated diseases arising from simple causes
an impossibility. Besides, the causes of disease
in plants will be much easier to ascertain than
in animals on account of the plants fixed po-
sition. Effects rather than causes are first CON
sidered III making the diagnosis Of q disease.
for the present, at least. The causes are much
easier TO ascertain and remove than their effects.
The following classification of the diseases Of
plants has Just been suggested by . German sa-
want: !. Effect of mechanical Influences as in
jury through lack of room for growth, and
wounds of various kinds. 2 Diseases caused by
an improper amount Of sunlight, warmth and
moisture, 3. Diseases caused by parasitic
plants. 4. Diseases caused by parasitic ami
mails. The last class Of diseases will be most in
tesesting to tho specialist doubtless.
Three kinds of remedies viii be applied to
these diseases: l. Substances that will kill the
insects, and not the plant, will be applied. 2.
Insects harmless to the plant, but destructive to
the plants parasites will be encouraged 8. The
injurious insects will be inoculated with eonta-
gious diseases. The respecter of life sbudders at
the Thought of so much destruction. A man who
could be comfortable when engaged in such
work, would certainly be without the magma {
ton or the penetrating eyes of the author Of
The Inhabitants of an Old Pear tree
L. l. j. MARTIN.