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[Market-farming] Round-up resistant pigweed in Arkansas
- From: "David Tannen" <david AT centerville.net>
- To: "Market Farming" <market-farming AT lists.ibiblio.org>
- Subject: [Market-farming] Round-up resistant pigweed in Arkansas
- Date: Wed, 27 Jun 2007 05:52:55 -0600
I pulled quite a bit of this from a small 5' x 100'
bed that wasn't properly mulched. I can't imagine a conventional farmer
with several hundred acres dealing with pigweed as it becomes a
superweed.
David
Suspected
glyphosate-resistant pigweed on upswing
Jun 26, 2007 10:27 AM,
By David Bennett http://deltafarmpress.com/news/070626-pigweed-resistant/index.html
Ken Smith is unsure of
the extent of glyphosate-resistant/tolerant Palmer amaranth in After spraying, more
farmers just arent getting a response on pigweeds. Theyll spray and most
pigweeds die while others just get puny. But, most alarming, is when we spray
and the pigweeds dont even get sick. Smith was alerted to
just such a field in Smith found a very
clean 100-acre field with a single blemish: a spot of perhaps 1,500 square feet
where Palmer amaranth had taken over. The pigweeds were solid with at least
several hundred plants. Since its restricted
to that small of an area, Smith suspects the plants probably came from the seed
of a single plant in 2006. The standard
procedure is to spray them with our sprayer. We did that and the pigweeds still
werent affected. So those weeds have been sprayed three times and theyre still
green and growing. Were normal rates
used? Yes, normal rates, although we sprayed one strip at a double rate. Those
pigweeds didnt appear to fare any worse. We collected some of the pigweeds for
the greenhouse, to study offspring. And when we left, we sprayed a gallon of
Roundup WeatherMax. A week after spraying
the WeatherMax, Smith reported, Im very sad to say the pigweeds werent
bothered at all. Thats after three shots at regular rates and another gallon.
My goodness, the implications are not good. Well suggest the grower disk the
weeds up and put out a soil residual to try and keep anything from
germinating. Are calls on suspect
pigweeds more frequent this year? Much more. Several days ago, I was in
When we visited him,
he was on a third trip across the field with Roundup and Staple, at that
point. I checked the field and told him, Youll get a few more of these
pigweeds with that mix. Unfortunately, you wont kill them. They may become very
sick, but theyll put out adventitious buds down the stem and theyll come
back. The farmer lamented
the fact that hed done everything he knew to do without success. And this was a
rather large area the field is probably 200-plus
acres. Such scenarios are
much more common this year. I probably get a call on tolerance concerns every
third day. In fact, were getting so many of those calls were backed up in
visiting the locations. Im going to as many as I
can. Is resistant/tolerant
Palmer amaranth spreading in situ or from seed or pollen movement? I think
were developing our own populations by reliance on glyphosate. Weve selected
pigweeds out for almost 10 years. Weve just scooted tolerance levels up the
scale. And once a few
pigweeds get by, the horse is out of the barn and running wild. These pigweeds
will produce massive amounts of seed, and theyre absolutely
prolific. But I also think this
is spreading with pollen. I think that avenue of spread is more dangerous than
we originally thought. What about suspected
ALS-resistant horseweed being found in But the ALS chemistry
is very site-specific in how it works within a plant. Again, when using it
were selecting horseweeds that can handle the herbicide. FirstRate, which weve
been using in soybeans successfully, will probably work for a few years before
losing effectiveness. The thing is, this
population of ALS-tolerant horseweed was found by accident. Its probably a safe
bet that there are other locations in the state that havent been found
yet. How good is the
possibility of the ALS-resistant horseweed also picking up resistance to
glyphosate? Thats very likely to happen, almost a given. Id be very surprised
if it doesnt happen. The good part of this
is most horseweed control is still built around the dicamba molecule. Farmers
want to get into the field early with dicamba. And as long as dicamba has been
in the market since the 1970s not many weeds have become resistant to it. So
there is a rather successful tool still available on
horseweed. e-mail:
dbennett AT farmpress.com |
-
[Market-farming] Round-up resistant pigweed in Arkansas,
David Tannen, 06/27/2007
- Re: [Market-farming] Round-up resistant pigweed in Arkansas, road's end farm, 06/27/2007
- Re: [Market-farming] Round-up resistant pigweed in Arkansas, Sharon and Steve, 06/27/2007
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