Imperial Valley press., 1929-08-17
BY FRANK BEYSCHLAG
Farm Advisor

The yellow alfalfa butterfly
which is now 50 prevalent itself
does no harm to alfalfa. 1t is direct
ly responsible. however, for its
greedy offspring, the green alfalfa
caterpillar which is doing damage
amounting to hundreds Of thousand F.,
Of dollars to Imperial Valley alfal-
ia growers.
The yellow butterfly mates when
one or two days old and begins
laying eggs the following day. Dur
ing her brief life OF about two
weeks the butterfly lays from 900
to 500 eggs. The eggs are most com
monty deposited on the upper leaf
surfaces Of young tender growing
alfalfa Which is two - eight inches
tall. The eggs are white or reddish
brown and are about one-siXtcenth
of an inch long. In three to seven
days the eggs hatch into tiny dark
brown syHndrieal worms less than
/ one-tcnth inch long. Soon after
feeding the worms take on 4 char
acteristic green color. The worms
feed voraciously and reach a full
growth Of ! Z inches in l. to -
days. The worms or caterpillars
then change into a yellowish green
pupac. They remain inactive in this
resting stage for about five to
seven days. Then the caterpilars
complete their life cycle by trans
forming into a butterfly.
Fortunately parasites, productions
insects, fungus and lastcrial dis
ease, birds, toads and even domestic
fowls aid in keeping the caterpillar
i'll bounds during most seasons :;
otherwise no alfalfa would be grown
in Imperial Valley. One parasite
destroys the eggs, several others
prey upon the catorpiIlars, another
eats ont the interior Of the pupae.
The most important natural control
is "a bacterial discaso which is fav-
orcd by high humidity and warm
weather, This changes both the
caterpillar and pupal stages into
hroWnish black soft dccaying
mass s..
A Farmers Bulletin on the AlfaI-
ia Caterpillar which may b. had
for the asking gives the following
summary of control measures:
Keep the ranch in best possible
cultural condition. Irrigata it often
and thoroughly, either immediately
before cutting or as soon after
cutting as the crop of hay can be-
removed from the ground.
Rcnovatc every winter and dur
ing the month ef August, or even
oftaner if possible, ny the use Of
a good type Of alfalfa reaovator,
thus disturbing any popae that may
be present and putting the land and
alfalfa in condition for growth of
succeeding crops.
Cut the alfalfa close 10 the
ground and clean, especially along
the ditch banks, borders. and turn
ing rows, as veil rs in the main part
Of the field.
Cut tine alfalfa carrier than i
The general rule. The proper time is
when it is just coming in bloom or
! is one-tcnth in bloom Watch fo.
oatcrpil!ars in the carly spring crop,
ard if many are observed and arr
about grown, cut the hay Il few
days before it is in bloom. and thus
save the next and future crops.
\ minimum amount of damage
occurs in fields shat are svstema.
ticaliy pastured all or q palt Of the
time.
Excessive moisture is conductive
to Il diseased condition of the
larvae, and thjs one fart is of the
greatest Importance in control.
When worms begin to appear in
numbers, if possible supply this
moisture by irrigation and thus as
sist nature to destroy the worms.
\ field shoull never be abandon
cd because the caterpillars threaten
the destruction of crop of alfalfa
before the hay can possibly mature.
Now it at once, cutting it low and
clean, thus saving part of the pres
cnt crop, and in 50 doing 5tarve this
generation Of worms and allow the
heat Of the sun to Kill great many.
Follow this by disking and then bv
either rolling or brush dragging.
and a great majority of any remain.
ing larya" win bn killed. The ground
should then be thoroughly irrigated,
and hN th.se efforts the future crop
will be assured.
Turkey and cbickons when ai-
lowed the run Of field VIII ke,p
tl' numhars af the catcrp.llars az
"a m.uimU,0
Th protection OF toads should
hr encouraged. aa tlry eat many ~
thesc INSECTS a, Wru as either iu-
.uru,, .rus.
II has beeu noted rhqt carrviu,
.ut only part off these raeoamop.
d"t105 win not at. all Times saw
the cr.p. The best results coma
WHOM oa' is thorough i'm his methods
toopNr'jaa among all growers IS
necessary to 1nprrs, completely an
insc at.act, Nn oc.asionU oa.-
hr,as has been known In r1 r