Plentywood herald. [volume] (Plentywood, Mont.) 1908-current, 1935-08-22
YIELD OF FIELDS IN
COUNTRY
is CUT IS PERCENT
Fly Cuts Off Grain Near Root
And Hibernates In Stem
Says Agent

Wheat pields in sections of Sheri-
dan county have been cut from 5 to
rs percent by a devastating parasite
called sawfly according to M. j.
Peterson, county agent who has
made an inspection tour of areas
which were believed infected.
Sawfly damage is noticeable along
the edges OF wheat fields. The wheat
stems are cut off about one inch
from the ground. 1t may be distin-
guished from Hessian fly damage by
the fine dust present in the stem
when sawflies have caused the dam
age, according to the county agent.
The flies attacking fields in the
Outlook country have taken a devas-
tating toll. Some fields are reported
to have been cut so percent while a
conservative estimates in fields dam
aged would be from 5 to Is percent
the county agent said.
All parts of Sheridan county have
not as yet been inspected for sawfly,
however, an inspection of the Medi-
cine Lake country and other sections
Of south Sheridan county revealed
that no damage had been done.
The presence of the sawfly,
coupled with rust and g~rasshopper
invasiOns has reduced what looked
as n OF Sheridan county's biggest
crops to a figure far below expecta-
tons.
Preventative measures are expect
ed to be taken to combat the sawfly
invasion, which Is a new hazard for
Sheridan county farmers.
County agent Peterson says that
the adult sawfly is a small black and
yellow wasp-like insect with dark
wings. 1t is about one-third Of an
inch long and first appears on the
wing late IN May and they continue
to fly until the middle OF July. They
are very inactive and spend most Of
their time resting on stems of grain
and grass. When they do fly, the
county agent says, they remain near
the ground and travel only a short
it is known, they require no food
other than water. The majority of
the eggs are laid In June.
How They Damage
The sawfly settles headdownward
on the yound wheat plants and, with
a pair OF saws at the end Of its body
cuts a slit through the leaf-sheath
into the Towering stem somewhere
below the developing head. Through
this slit 1t forces a small white egg.
Any number OF sawflies will lay their
eggs in the same stem. One OF the
grnbs that matches from these eggs
will eventually kill all the others
that are present.
The small grubs that hatch from
the eggs burrow downwards within
the hollow straw and eat their way
through the solid nodes in so doing.
The straw. through which they have
passed, is partly filled with a saw
dust-pke material. The head, mean
while, develops normally. Though
there Is SOME reduction In the yield
OF attacked stems this is not very
serious BY the time the head begins
to ripen, all Of the grubs are below
ground inside the straw. They now
turn round so that their heads are
uppermOst, and cut off the straw at
q point that Is usual about one inch
above the ground.
tlIcl piuBSIuS lut OPcn 0iu VI LuV
stub with "sawdust," the grub spins
a delicate silken cocoon in which it
remains more or less inactive until
the following spring, when 1t pupa-
ties and later escapes as a sawfly by
pushing out the plug.
Plants That Are Attacked
Originally sawflies laid their eggs
only in native grasses. Now, how
ever, they lay them as readily in all
grain crops. The grubs can mature
successfully only in spring wheat, in
spring rye and In a variety of native
and cultivated grasses. Although
eggs are laid freely In oats the
grubs that hatch from them die al
most Immediately and do no damage
to the crop. They live somewhat
longer in barley, but very rarely
mature.
Effect Of Climate on sawfIy
Moderately dry seasons are favor
able to sawfly abundance. Not only
do they do more damage in such
seasons, but they will be present In
increased numbers to attack wheat
in the following year. Excessive
moisture. oil extreme drouth, in June
and July reduces their numbers: but
they have appeared In a dis
trct they will always be present in
sufficient numbers to cause severe
losses when climate conditions are
favorable to them.
Control Measures
Deep fall blowing. rotation OF crops
trap cropping and seeding Of
Bronze grass are control measures
according to the county agent. Bull
letins are being issued from the
office this week on the life
and habits Of the fly and the
various control