. . . . Soybean Aphids May Have Caused Up to 13 Bushels Per Acre Yield Loss in Some Fields South of I-90 in 2004 . . . .


   
Have You Soybean Aphids Today?

Update September 1, 2004:  I am of the opinion that it is too late to treat for
the soybean aphid in South Dakota.  From Aberdeen to Beresford, most of the
soybeans are already past the R6 (green bean) stage and the leaves are already
senescing (turning yellow).

You had your chances to do something about the soybean aphids from July
through August.  If the leaves in your beans look shiny, then the damage had
been done.  Were you caught sleeping or trying to use the 250 threshold?

However, it is not too late to treat for the bean leaf beetles as these insects
will continue to feed on the green pods.  See pictures and recommendations
below.

Scary Update (Friday the 13th):  A lot of our soybeans are now at R5 or beginning
seed stage.  Soybean aphid numbers will  peak at this stage, then start declining
thereafter.

If you do not have soybean aphids at R5, then you are "out of the woods" with
this insect.  However, soybean fields still at R3 (beginning pod) will still need to be
scouted and treated if necessary.  Most of the soybean aphids being found at the
moment in southeastern SD are on R3 soybeans.

After R5, you still have to worry about bean leaf beetles.  These insects will keep
on feeding on soybean pods until the pods turn yellow, literally.

       

I hope that all spraying, whether for the soybean aphid or the bean leaf beetles, will
have been done by this weekend.

"I-can't-find-them-aphids-while-driving-around-in-my-air-conditioned-pickup-truck"
is a common refrain from some scouts (graduates of so-called major universities).

"It is so lonesome out there that you can write a sad song about it", according to
Buford 'The Buff' Malarkey out there in Elk Point.  I did not ask Buford whether the
song will be to the tune of Achy Breaky or Stardust.

In the meantime, over 15,000 acres of beans have already been sprayed in
Yankton County.  Chris Nelson with Yankton Ag. Services (661-1518) can give
you an update.  I spoke with Chris yesterday (8-12-04) while I was spraying
soybean aphids with some really nasty stuff out there in Clay County.  The sound
of spray planes permeated the air all day yesterday and today while I too was
spraying our fields.

Chris is an alumnus of SDSU and majored in Plant Science under Dr. Ron
Gelderman.  No wonder he's good.  Those Nebraska grads, like Buford,
cannot find the aphids!  Too much football news in that pedia site.  Don't
even get me started with the gophers and cyclones.  They don't even play
good football.  Yes, I intentionally left the "g" and "c" in lower case.

Another distinguished agronomist is Greg Pirak out there at Yankton Valley Ag.
He updated me last week (8-4-04) about soybean aphids in his area and
mentioned that they too have been quite busy in dealing with these insects.
Greg can update you on how many acres they have treated so far (267-3100).

Greg is an alumnus of UC-Davis and is originally from the great state of Ohio.
Thus, it now appears that only SDSU and UC-Davis grads found the soybean
aphid on time here in SD.  My buddies Tom and Keith across the border got
caught sleeping then started to criticize my thresholds.

There are still a lot of winged soybean aphids flying around.  These winged ones
most likely came from "nursery" soybean plants where the aphids are now over-
crowded and thus started to send off winged ambassadors of ill will.

Below are "postcards from the soybean fields" from my traversals from Yale
(yes, the one north of Iroquois) to Beresford to Canton.

Enjoy the sights. And, yes indeed, we still have soybean aphids today.


     

     

       


For more information visit our sites:  Soybean Aphid in South Dakota

                                                          Economic Thresholds in South Dakota

                                                          Threshold Calculator for South Dakota

                                                          Bean Leaf Beetles in South Dakota



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 Web Posted on Friday, July 16, 2004. Last Updated on Tuesday November 2, 2004 by Mike Catangui..