Skip to Content.
Sympa Menu

market-farming - [Market-farming] Surround WP for corn earworm control

market-farming AT lists.ibiblio.org

Subject: Market Farming

List archive

Chronological Thread  
  • From: "Marlin Burkholder" <glenecofarm AT planetcomm.net>
  • To: "Market Farming" <market-farming AT lists.ibiblio.org>
  • Subject: [Market-farming] Surround WP for corn earworm control
  • Date: Tue, 7 Sep 2004 22:36:27 -0400

For the past several years, I have reluctantly relented to using an
insecticide to keep down earworms on sweet corn and thinking at the same
time that if there is a nonchemical alternative I would want to try it. I
had already tried various Bt products, mineral oil applied to silks etc, and
been dissatisfied with their efficacy. I looked at the Zealator program
promoted by JSS and the University of MA and decided that this too would not
be cost effective in my operation.

A year ago I bought some Surround WP and used it on some fruit trees but
didn't follow through like I should have. Despite my lackadiasical use of
the product I was still impressed enough to keep it around and use it again
this spring. My enthusiasm was then somewhat stymied when one of the
apricot trees I drenched especially thoroughly with it suffered more than 50
% defoliation.

The first sweet corn patch this year got three successive insecticide
applications beginning several days following silking initiation and spaced
5 - 7 days apart up until 3 or 4 days prior to harvest. Worm control was
excellent, but I didn't enjoy the task of emailing my CSA clients to confess
to them the fact that I had digressed from my otherwise mostly organic
farming program to do something that I thought was relatively safe and
necessary, but nevertheless a contradiction of sorts of my basic operating
philosophy.

Then the idea hit me that if Surround is supposed to repel the coddling moth
that lays the eggs that produces the imfamous worm that eats it's way into
apples and other fruit, why wouldn't it work to repel the egg laying moth
that produces the worm that infests sweet corn? Though there is no label
for application of Surround for earworm control, I considered it worth a try
on my second patch of sweet corn.

I decided to do one insecticide application following appearance of silks
because I was concerned that the application of Surround at this stage might
interfere with pollination. I then put on the Surround one week later in
leu of the second insecticide application when pollination was complete and
silks were starting to dry up. This I theorized, would discourage the
second round of egg laying which occurs after the initial insecticide
application wears off. If my hunch is right, I shoud see less earworm
infestation and minimal damage even if some the second instar does get past
the Surround before harvest commenses. The weather had stayed dry, so one
week later the white film was still intact and I was busy enough with other
activities that I didn't put on another Surround application in time for the
normal 3rd insecticide application.

As expected, I found some worms as I began harvesting the crop, but most of
them were small and the damage insignificant with an infestation rate of
around 50%. Not as good as the full insecticide program, but not bad either
for a first try. I wonder if the Surround would have worked better if I
would have sprayed walking in both directions through the patch, insuring
more thorough coverage on both sides of the ears and leaves. Maybe a second
Surround application one week later would have been worth while. I'll
probably try this again next year with a few extra tweaks. I would be
interested if anyone else has experimented with Surround for corn earworm
control. This ought to be a good one for university research.

Marlin Burkholder
Virginia





Archive powered by MHonArc 2.6.24.

Top of Page