The gazette-times. [volume] (Heppner, Or.) 1912-1925, 1915-02-11

as tne cnalclS-1ly, does us de-
= structive work in clover or al
falfa seeds, from the Gulf Coast to
the northern limits of the United
States, according to the United States
Department of Agriculture special
ist, who has personally seen the wide
spread devaStations of this pest. By
harvesting severely infested crops, by
cleaning fence lines and ditch banks,
and by Winter cultivation the grower
of alfalfa seed may help to control
this insect. A new Farmers Built
tin (No. 636) entitled THE Chalcis-
Fly in Alfalfa Seed" gives the details
of these methods of control, and may
be had free of charge on application
TO the Department.
Pest Resembles Gnat.
The chalcis-fly under the micro
scope is a formidable-looking insect,
but when seen in the field it is fire.
quently confused with the gnat.
These pests may be seen in great
numbers flying over alfalfa-seed
shocks and swarming over the sickle
bar when the alfalfa is being cut.
The eggs are so small as to be in
visible to the naked eye and are de-
posted through the soft, green seed
pods directly into the soft seeds
when the pods are about nalf-grown.
Immediately upon becoming a fly,
the insect eats its way out through
the shells of the infested seeds, then
through the green pods. Large por-
tions-of the seeds are followed out In
this manner, when they are still
green and growing.
Recognizing Infested Seeds.
The infested seeds which still con-
tain the living larvae of the insect
may. be recognized by their abnormal
shape and usually by the dull brown
color. Some of the infested seeds,
however, retain their natural color,
but they always lack the glossy ap-
pearance of normal seeds. The ex-
tent to which alfalfa seeds is dam
aged by the fly is not generally ap-
parent, owing to the minuteness of
the insect and because it's destructive
work is accomplished within the
grow wing seeds. The alfalfa-seed
grower can only estimate the per-
centage of his crop destroyed by open
ing a large number of the seed pods
and observing the infested seeds.
Harvesting Infested Crops.
An alfalfa field Is frequently
found with such a severe infestation
by chalcis-flies that the grower con-
siders it of insufficient value to be
harvested and simply drives in herd
of cows to pasture the crop. With
regard to the control of the chalcis-
fly for the protection of future seed
production, this is costly mistake
Observations show that many of the
pods burst open, while others are
trampled to the ground. Here great
numbers of infested seeds offer fa
vorable conditions for the hiberna
tion of the chalcis-fly larvae.
These, as mature flies, will infes
the seed crops the following Spring
Under such circumstances the croI
should be moved, removed from thu
field and stacked. 1t may then bt
used as rough fodder; and If the re
naming straw Is burned in earl.
Spring the alternating larvae will b.
destroyed.
Cleaning Fence Lines.
The following facts emphasize tn,
importance of cutting the alfalf'
along ditch banks and fence lines, a
well as in the fields:
1. The earliest seed pods ar
found to develop on the isolated AM
vigorous growing plants found in suo|
places.
2. The earliest pods have an espe
cially large percentage Of the seed
infested with chalcis-fly larvae.
8. The chalcis-fly larvae are abl
to pass completely through the firs
generation in the earliest pods befor
the regular seed fields are sufficient
ly advanced for oviposition.
This cutting should be done wit
the harvesting of each hay crop, be
fore the seed crop is grown.
1t Is sometimes necessary to hav
two or more irrigation bitches run
ming parallel, making it impracticabl
to cut the alfalfa between them.
such cases it is economy to fence tn
bitches and use this land as a smal
Summer pasture, thus preventing tn
development of alfalfa seed pods an
the chalcis-flies.
Winter Cultivation.
In the process of harvesting th
seed crop many pods containing in
fected seeds fall IN thp pround Her