Northern Wisconsin advertiser. [volume] (Wabeno, Wis.) 1898-1925, 1916-11-17

sian soldiers In Revoiu-
- tionary days.
1t is widely distributed and does
more or less injury locally every year.
Like most of our destructive pests,
however, it appears as general
scourge more or ess periodically fol-
lowing series of favorable years. One
or more dry summers followed by mild
winters usually brings on Hessian fly
troubles. The dry weather keeps the
pest in the resting condition in the
stubble and also prevents the blowing
under of stubble and then with the
early fall rains wheat is sown early
and the flies appear and lay their eggs
on the young wheat. These are the
ideal conditions for an outbreak Of the
fly.
The injury to wheat is due to the
work of the maggot or larval stage of
the fly. The small, dark, winged, mos
quitOlike fly does not attack the wheat.
The maggot rasps on the tender plant
with a pair of sharp fangs, causing
flow Of sap which it drinks. The young
wheat, when attacked in the fall, stops
growing and turns yellow. Usually
this first appears where the ground Is
poorest, but if the infestatiOn is bad
1T will finally show up over the whole
field. If the weather is favorable til
1ers are usually produced and the crop
is not completely destroyed, unless
the infestatiOns be very severe. In
the spring the wheat may start Off
strong and thrifty, but as soon as the
rains cease and the spring brood of
maggots begins to feed, the wheat stops
growing and turns yellow. When the
pest is not too abundant the wheat
may head out and produce partial
crop, though the heads do not fill prop
erly and the grain is light. The lodg-
ing or falling of wheat begins about
the time of heading and continues I'M
til it is ripe. In case of severe infesta-
tons no heads form at all.
Develops Like Other Flies.
The development of the Hessian fly
is similar to that of other flies. The
adult winged fly lays eggs on the
wheat leaves. These hatch into very
small, whitish maggots which feed on
the sap of the plant. When nearly
full fed the maggOt may appear green
due to the green sap 1t contains. When
full fed the maggot turns brown and
takes on the shape of q flaXseed. The
maggots in the f1xseed stage are of
ten packed together in groups of from
six to thirty in the base of a wheat
plant. Within this brown case the
small maggot changes to the resting
or pupal stage and later the fly
energies.
In Kansas and other states of about
the same latitude, there is normally
one fall brood, one full spring brood
and a later partial spring brood of
flies. From the last of August to the
middle of October the small black mos
quitolike flies continue to emerge and
lay eggs on the leaves of wheat Each
fly lives but a few days. The females
lay an average of 100 eggs. When the
eggs hatch the small maggots pass
down between the leaf and the small
stalk to feed on the stalk. By the time
cold weather comes, the maggots are
full fed and change to the brown flax
seed stage. In this form they spend
the winter below ground in the crown !
of the wheat plant. About the middle |
of April they hatch and the first brood
of HeSsian flies appears. These flies
lay eggs which hatch during May, pro-
ducing the spring brood of maggots.
I'm case of a warm, damp spring these |
may mature and produce a second
brood of flies which pass the summer
in the wheat stubble in the flaxseed |
stage. 1t is the brood which is main |
ly responsible for the destructive fall |
swarms of flies.
While this is the normal cycle, some |
wears additional secondary broods may |
appear and during a dry spring the |
secondary spring brood may not APP
pear ut all. Cool, dry weather always |
retards the development of the fly |
while warm, damp weather hastens it. |
If there is an excess of moisture dur |
ing the summer the flies may come |
from the fiaxseed stages in the stub |
bile and deposit eggs on volunteer
wheat producing a secondary summer |
brood In the same way a small sec |
ondary fall brood may appear during |
November in case of excessive rainfall |
though such cases are rare. Late sown
wheat is seldom attacked except by !
the spring brood which migrates in |
from infested fields.
The HesSian fly is most effectively |
controlled by proper methods of farm
practice. The destruction of all In
tested stubble very early and the SOW
ing of wheat late enough in the fall /
HnN0CNChTI0Nc