|   Past Issues    |   Soybean Aphid in South Dakota    |    Soybean Defoliators    |   History of the Soybean Plant  | 

Many European Corn Borer Larvae Survived the Winter

   

                                         (Click on the thumbnail to view a bigger picture)

Due to the very high number of European corn borer moths observed last August (2001)
at the SE Research Farm near Beresford, and the relatively mild winter, we wondered
how many European corn borer larvae successfully overwintered in the corn stubbles that
had been on the field since October of last year.

We collected 110 pieces of corn stubbles at random from various fields at the SE Research
Farm on February 15, 2002 after the mild November to January months.  A cold snap happened
after the first collection date so we collected another 400 stalks on April 2, 2002.

The corn stubbles were brought to our laboratory then dissected using a curved knife
for live European corn borer larvae.  Dead larvae were not counted.  We did not know whether
the corn stubbles were from Bt or non-Bt hybrids.  I sure hope that all of the stalks were
from non-Bt hybrids!

I would like to thank SDSU students Dave Mills and Richaille Rus for collecting the corn
stubbles and dissecting them in the lab.  Dave is a graduate student in entomology while
Richaille is an undergraduate student.

As you can see in the pictures above, many European corn borer larvae survived the
mild winter, and the February-March cold snap.  The data are as follows:

The bivoltine ecotype European corn borer is present at the SE Research Farm near
Beresford and SD counties along and south of I-90.  The overwintering survival of ECB
larvae at the SE Research Farm may or may not be representative of the whole bivoltine
ecotype area.

Bivoltine ecotype larvae that survive the winter and spring cultivation will metamorphose
into pupae, then into adult moths that will typically start flying in early-June at the SE
Research Farm near Beresford.

The nighttime temperatures in June will determine whether we will have a significant
or "high" corn borer year.  If the nighttime temperatures were in the 40's, then the moths
will not be able to deposit their eggs efficiently on the corn leaves.  However, if the night-
time temperatures were in the 50's or 60's, then we could expect a "high" corn borer
year this year.

We have not measured yet the overwintering survival of univoltine ecotype larvae.
Univoltine ecotype European corn borers occur on counties along I-29 north
of Dell Rapids.

For more information on the European corn borer in South Dakota: 

 Last Updated on Tuesday, April 9, 2002 by Mike Catangui

| Extension Entomology Home Page | Archives | ECB Moth Flight 2001 |