Mountain Home Republican. [volume] (Mountain Home, Idaho) 1915-1946, 1925-04-17

| the field at one time in 1924, but
they attacked the plants at diff
erent stage of growth and fed for a
shorter period of time. In 1928, SO
days elapsed after the first spray was
applied until the numbers of worms
began to drop off naturally in spite
of the climatic differences, certain
facts were CLEANED from the exper-
iment which will serve in any eli
mate.
From the time that worms be-
come numerous enough to cause
injury until they have reached their
greatest numbers and stopped feed
ing, is the critical period in relation
to the amount of damage done. The
greatest number of worms in 1924
occurred 20 days earlier than in
1923 and injurious numbers fed on
the first crop for % days less than
in 1923. Instead of less weevil in
1923, there were actually more in
the field at one time in 1924, but
they attacked the plants at differ
ent stage .of growth and fed for a
shorter period of time. In 1928, 80
days elapsed after the first spray was
applied until the numbers of worms
began to drop off naturally but cor
responding period of time in 1924
was but five days. A spray is eff
fective for approximately 10 days af-
ter its application when plants are
growing normally. This explains,
the department thinks, a second
spray was necessary in 1923 but of
little extra benefit in the year fol-
lowing.
In 1928 all the eggs Matched out
during the months of May and June
and were present in the field even
after the first crop had been cut. In
1924 practically all the eggs were
Matched out by May %. June OF
1928 was so wet and the alfalfa
weevil matured at a corresponding !
rate of speed A condition existed,
therefore, where a smaller number |
of weevils, eating over larger per-
iod of time, did a correspondingly
larger amount of damage. In 1924
the weevil injury nearly all was
done by May 25, worms began to
cease feeding and many fields had
made certain amount of natural re-
eovery. The lack of moisture and
he intense heat of early May had
he effect of Fastening the devlop-
nent and the feeding of the weevil,
If reducing its feeding period and re-
arding the growth of the alfalfa.
Most of the growth of alfalfa was
made after the weevil had quit feed
ng upon it.
The years 1921, 1922 and 1928
we're quite similar as regards the
development of the weevil and the
injury caused by it so they may be
aiken to represent more nearly a
formal condition than does 1924. 1t
5 safe to assume that 1925 will be
lore like the first three years than
Ike 1924 and that farmers may rea-
onably expect damage from alfalfa
yeevil again this season.
Entomologists have made minute
urvey of fields and have found many
reevil beetles surviving, even after
II crops of hay had been cut. There
re persons who believe that the para
tic enemies of the weevil have it
nder control, but others maintain
he extreme drouth and heat of last
lmmer killed many of the weevil.
9th of these suggestions are disput-
l by the department, however, be-
luse of evidence that an abundance
weevils entered winter alive after
ley were supposed to have been kill
| by parasites or weather. 1t is
ointed out that the parasites would
ave killed them in the worm stage,
at all.