Payette enterprise. (Payette, Canyon Co., Idaho) 1909-1935, 1914-06-04
Kill Slugs
: Saue Trees
Expert Tells of Danger That Threat
ems Cherries and Pears Proper
Remedy Will Save Them.
BY T. II. Parks.
Field Entomoiogist, Idaho Agricul-
turaI Experiment Station

turaI Experiment Station
The slugs that deyoured the foliage
of the pear and cherry trees in the
fruit growing sections of south Idaho
last season, will probably be as abun.
dant this summer. A recent inspect
ion of someof the pear and cherry
orchards in the Boise valley shows
that the eGgsfof the first generation
of these slugs are already deposited
in the tissues of the leaves. Many
chorry and pear leaves are noticed to
have one, or several, small, dark
brown spots on Their upper surfaces.
In the center of this spot is found tie
egg which later develops into the
Shiny brown slug that feeds on the
upper surface Of the leaf, leaving only
the veins and membranes. Wien
present in large numbers they cause
the leaves to become brown and the
trees to lock as though it hal been
scorched by fire.
Now Laying Eggs.
The parent of the slug is shining
black fly with four smoky transparent
wings and about as large as a honey
bee. These flies are now numerous in
the cherry and pear trees and are de
posting eggs in the tissues Of the
leaves. A few eggs have already
hstched, but The majority of the slIgs
will not be feeding for at least 10 day
The young iarva makes its way to the
1per surface of the leaf and begins
Feeding there, When the slug becomes
fpn grown it goes into the soil to a
depth of from one to three inches and
there changes to a pupa, from which
emerges the fly to lay eggs for a Sec
ond generation In July and August.
There are two breeds in Idaho and
judging from the number of eSss now
deposited the first generation of slugs
will probably do much damage to the
foliage unless checked by spraying
White Hellebore Is Good.
The pear aud cherry slug can easily
be controlled by sprays as it is sus.
ceptible to poisons. Arsenate of lead
applied at the rate of two pounds of
paste or one pound (powder) to each
90 gallons of water, serves to control
them. This should be applied to the
foliage as soon as the first slugs are
known to be feeding and before they |
have seriously injured the tree. Last
season spraying Of cherry trees was |
delayed because the fruit was ripen-
ing and it was feared the spray would |
effect the marketing of he fruit. |
When fruit is riDening at thesame |
time that the slugs are present white |
hellebore should be used at TIE rate
of one pound to so gallons of water. |
This is safe to use as it loses its pois-
oning qualities after two or three day
exposure to the air and quickly kills |
the sllugs. The hellebore must be |
fresh and free firm adulteration to be
effective. 1t can be used with safety |
en- all ripening fruit.
Where only few young trees are
infested with the pear and Cherry slug
they can be busted with air s!ackeS |
lime or fine road dust to kill the |
larvae Frequently trees located along
the highway are proteced from slugs
because of the dust being carried into |
them by the wind and blown upon tie
bodies of the slugs.
All cherry and pear trees should be
inspected AAgring early June for the
presence of tn slugs and as soon as
they commence feeding, spray with |
arsenicals or hellebore. This will pro
tect the trees against injury from the
second brood later in the summer, ( /
Judging by the number eggs now
being deposited the injury will be |
fully as great this summer as last, un
less they are KILLED by sprays.