The San Francisco call., 1906-09-16

winch all the laws Congress can ever
pass is powerless to exclude.
These pests are mostly microscopic
in size and their power of reproduction
is almost infinite. They seem to exist
for no other purpose but to reproduce
themselves. One of these introduced
into a State as large as California
needs only time to infect the whole
area, whether they possess the power
of Iocomotion or not. The pear blight,
which the horticulturists of the Sacra-
mento Valley met the other day to
discuss ways and means to overcome.
is only microscopic speck. so minute
that a lens of very high power is re-
quired to bring it into the ranges Of
visibility, yet the blight has travelled
from the far Eastern States of the
Union. swept over every Eastern and
Middle State, Wisconsin, Illinois and
the States beyond the Mississippi. and
has actually exterminated every pear
orchard in all that vast stretch of
country. In no State in the Union, out
side of California. is the pear raised in
commercial quantities. Only isolated
trees, protected from the blight for
some mysterious. unknown reason, can
now be found. Some few years ago the
blight appeared in this State and up
to this date has killed every pear
tree in the San Joaquin Valley. It is
now spreading ruin and desolation
among the pear orchards of the north
ern part of the State. The life history
OF the organism which causes the blight
is perfectly well known to entomolo-
gists. 1t is meteorological in its ma
ture and looks like the comma bacillus,
SO familiar to scientists. It's shape is
oblong and its methods Of reproduc-
ton is by division. each part forming
a complete organism with independent
powers. Increasing in geometrical
progression, the numbers OF the pest
are beyond expression. It's effect upon
the pear tree is not unlike consumption
in human being. Infection is shown
by a loss of vitality in the part at
tackled. Any branch where the blight
finds lodsment decays and dies. Upon
this tantalizing bacillus arsenical or
any other spray has not the slightest
Impression The only effective remedy
is in surgery. cutting out. wide and
deep, the parts attacked and burning
the cuttings. Even the knife used In
operations must be disinfected every
time il is used or the clinging bacillus
will further spread the disease. With
the utmost care the blignt- can be kept
under by means OF the knife. The
orchardist must work late and dill
gently and he will gain reward in the
monopoly he will secure as a grower of
this matchless fruit
Bacillus Has No Locomotion.
The bacillus. the cause Of the pear
blight, has no power of locomotion
is in reproducing itself. yet how has
il spread until there is not a section of
the 100000 square miles in the United
States where II has not shown itself?
This was once as perplexing question
for the most erudite entomologists to
answer as 1t is TO any laymans but
careful investigation proved that the
germs Of the pear blight are carried
from tree to tree on the bodies. wings
or legs of winged insects in their visi-
tation of blossoms in search of the
nectar which each distills. The intro
duction of the pest to California or
chards was doubtless through nursery
stocks sent from the East or else from
fruit imported from Atlantic ports.
That devastating insect known as
the San Jose" scale (the enterprising
city of the Santa Clara Valley objects
to the sinister appelIation, but must
bear it) is another fruit pest which
since its introduction into California
haa deua stated rnilllnns Of mach nr=