Second Brood Corn Borer Damage

    Our Bt-corn crew is almost finished splitting stalks of corn at the Beresford station.
It now appears that while the first generation did not infest many stalks, the second brood
did infest 50-60% of the corn stalks and ear shanks.  This infestation level is significant.
We have not harvested the crop yet but I expect at least a 5 bu/acre reduction in yield in
some untreated non-Bt hybrids.  In general, it was quite hard to convince growers to scout
and treat the second brood back in late-August to early-September perhaps because of
low corn prices.  We will know after harvest whether treating for the second brood was
cost effective after all.

  Eureka (Sunflower Midge Seen There)    

    On August 13, 1999, I received sunflower samples from Eureka showing injuries due to
the sunflower midge.  The sunflowers were collected by Brian Naber (Monsanto Agronomist)
from an 80-acre field east of Eureka.  Brian has informed me recently that yield loss was about
5% in that field.  Hybrids with some degree of tolerance do recover from midge injury and
produce seeds.   I am of the opinion that this was what happened in Eureka.  A field in Roscoe
last year suffered a much worse reduction in yield (up to 70% in some areas within the field).

   As the sunflower harvest continues, be observant of any gnarled or deformed flowers
especially along the edges of the field.  This is usually an early warning of what may happen
next season.  A list of midge-tolerant hybrids will be available after harvest.  My colleagues
from NDSU (Dr. Gary Brewer and Dr. Larry Charlet) prepare the list after every season.

Just In: Gypsy Moth Found in Lake County! (e-mail me for more info)

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