The Yale expositor., 1918-08-22

Die charge 40 l1ttle WhSullke lnSeFl'
resembling the ones that originally
laid the eggs IT, the straw, and fly
away in search of the new crop OF
wheat which is just beginning TO nice
ly lengthen out. They will fly TO some
distance in this search, at least half
mile, and perhaps farther. The Gus
tom of using wheat land for clover
makes us hesitate to pillow under the
stubble, which would otherwise dis
pose of the adults. The greatest dan
ger comes from putting new fields or
wheat near old unp.owed stubble hen
the stubble is known to be badly In
tested with these joint-worms.
Two Kinds of Worms.
Besides the cop,mon joint-worm just
mentioned, there is another one far
less common in Michigan, and which
is at present restricted to- few To-
calities. In this species the leaf
sheath becomes involved I'm the SWELL
ing and the diseased sections have
wrinkled, gnarled and knotty appear
ance. Plants attacked by this rarer
species of joint-vorm often fail to FIJI
out at all. The heads sometimes fail
TO come out, and wher they do they
usually contain nothing of any value.
! In order TO gain an idea of the con-
dition OF affairs in the state as a
whole, a survey has been conducted by
Miss Eugenia Mcdaniel, member OF
this department, aided by Don b.
! nj ~ rfD
A. C. Conger, assistant professor in
! the department of zoology. the various
! county agents and members of the
Michigan Crop Improvement associa'
ton. AS result of this survey, we
are led to believe that there is belt
of well-established infestation which
starts in Van Buren, and Allegan
counties and which extends straight
across the state through Barry, Eaton
and Ingham TO Livingston county.
With these counties are included
parts of Ionia, Clinton and Shiawassee
counties, notably their southern
halves. jackson and Washtenaw
counties also have suffered quite Sc
verely. This area of oval form eX-
tending east and west across the state
has evidently been the center of in
festation. although all parts of the
state, apparently wherever wheat Is
4 grown i'm the lower peninsula, show
more or less of the work to be pres
ent.
The rarer and more serious species,
I. vaginicola, is present only very
sparingly except that there is an in.
vaded belt included in Livingston,
, Oakland and MacOmb counties and
also one Ia Saginaw county.
When the presence of the joint
worm in our state first became appar-
ent, the situation appeared as alarm
ing in the light of ou, pressing need
for wheat, but since investigation has
progressed to this point we are becom-
ing greatly treasured, because from
the immense numb err of samples sent
in from all over the state we
have been able to rear clouds
of parasites. These parasites are
small, wasplike creatures, that lay
their eggs in the larvae of the joint
worms, resulting in the destruction of
the pests. We know that ordinarily
the parasites hold the pests In nearly
complete subsection, and the presence
of the parasites at this time shows
that their work is progressing and
that the invasion of the pest is likely
to be soon thing of the past.
Recommendation.
The rincipal source of infestation
Is the improved Gtubble, which is left
unplowed because of the seeding OF
clover. 1t is desirable TO put new
wheat as far from such stubble as may
be. When the infestatlon Of the ,om.
mon tritici involves more than hall
the wheat plants, 1t may be well to
substitute Rosen rye on that particu'
lar farm. smaller percentage OF
plants infested by the more serious
form, I. vaglnicola, would seem TO war
rant the substitution. This advice ap
plies merely to the coming fall sow
ing.
1t has been found that a raking OF
the stubble late in the fall with side
delivery rake will make 1t possible &c
| COlltCl uIu Jul II a. IiOpOl Niph vi
the infested stubble. If the catch OF
clover happens to be poor II is, OF
course, advisable TO pillow the stubble
early in the fall, and thus to do away
with the danger of infestation In thai
particular field. In no case SHOULD
one SOW wheat after wheat this year
The Hessian fly. fortunately. is not
plentiful, except locally, but 1t Is with
us, and liable to make Itself felt II Civ
en- a chance. We are. therefore, rec
/, ommending that in the lower third Of
the lower peninsula the date Of sow
; ing be from the 10th to the 25th OF
September, and that the time he grad
ually extended as we proceed nortl
so as to include from the LIST to tn,
18th in >the northern part. Where thu
. Hessian fly Is known to be present, i
will be safer to sow near the lattel
. dates.
Fix II Today.