February 14, 2017
Weed Resistance Series
Giant Ragweed: 
Another Battle in the Field
Giant ragweed encroaching on corn field
In the last Agronomy Update, this series on herbicide-resistant weeds looked at waterhemp; now the conversation moves to giant ragweed.
"This herbicide-resistant weed is showing up in [our] area," according to Bob Marquette, Federated agronomist at the Albertville location, and "without proper management [giant ragweed] will find its way to other parts of Federated's trade area, if it already hasn't."
Giant ragweed resistance was first found with Group 2 herbicides (ALS-inhibitors) in the late 1990s in the "I" states (IL, IN, IA) and Ohio. "You probably know [Group 2] herbicides as Pursuit and Raptor," said Marquette.
"Resistance with giant ragweed is not new," he said, but "what is new is its resistance to Group 9 (glyphosate/Roundup®)." Resistance to what has become the go-to herbicide started showing up in the last few years, and is now confirmed in 11 states across the Midwest and southern U.S.
Resistance was built through repeated use of glyphosate year after year, first in soybeans and then in corn. "We found problem fields in both crops in Albertville this past growing season," said Marquette.
Giant ragweed is a "huge problem because of its competitiveness" and the fact that it produces a "massive number of seeds," Marquette noted. The battle with these weeds will intensify if growers don't take action. And the answer lies in modes of action.
As discussed in previous articles in this series, multiple, layered modes of action are being touted as the best option for achieving the desired level of weed control. And multiple, layered modes of action translates as "pre-emerge treatments followed by a solid early post-emerge program, and possibly a second post application," said Marquette.
"The new Roundup-Ready 2 Xtend® (dicamba) weed control system looks like it could be one piece of the puzzle" to get or keep control of giant ragweed, "but it needs to be used in conjunction with a good pre-emerge program to get the results we're after," he said, emphasizing that RR 2 Xtend is not a stand-alone product.
The battle rages with herbicide-resistant weeds. Talk to your Federated Agronomist to determine what products and programs should be in your weed-control arsenal.
Corn Grower Workshop Topic
Liquid Corn Starter 
Adds Value Early On
corn seedling
All across Federated's service areas, a pop-up, in-row starter is recommended to get corn off to a fast and strong start, according to Tim  Stelter, Federated agronomist at the Osceola location.

"We have a clear liquid that is 100% ortho," said Stelter, "and we have XLR-rate™ that is 80% ortho and 20% poly, which is a high-quality, seed-safe starter fertilizer (7-23-5) that mixes well with other micronutrients, especially zinc, the critical nutrient for corn development." (XLR-rate can also be used later in the year as foliar feeding.)

XLR-rate, a CHS product, can be combined with USA500, a Rosen's product, for complete pop-up nutrition on corn. It has four active ingredients, including zinc, that help release the phosphate tied up in the soil. USA500 also increases the availability of nitrogen, sulfur, and other important nutrients in the soil.

"These products are easy to handle, environmentally friendly, tested, and reliable," said Stelter. Whether it's applied in traditional two-by-two placement or in furrow, there's good value in start-up fertilizer.

Liquid fertilizer starters will be part of an in-depth discussion at next week's corn grower meetings (see info at right). Talk to the Federated Agronomists at the Corn Grower Workshops.
Beating the Problematic Weeds
Federated recommends herbicide programs designed around the problematic weeds, and "more often than not, we are seeing waterhemp and giant ragweed together," said Kevin Carlson, Federated's senior agronomist.
Carlson said, "From a pre-emerge standpoint, we have to ask what works on both [waterhemp and giant ragweed]?"
Bryan Thompson of Rosen's said, "Blanket® 4F is a liquid straight goods sulfentrazone product that's one of the best pre-emerge active ingredients on the market for waterhemp." In the fight against giant ragweed, Blanket 4F tank mixed with Sonic® or Authority® First can be an effective choice. Thompson said this "agronomically sound" tank mix offers "considerable savings to the grower" when both weed species are present.
"Blanket 4F is comparable in formulation to FMC's Spartan® 4F, and it works well as a supplement to Sonic and other popular pre-emerge herbicides," Thompson said.
Sonic + Blanket 4F
A tank mix of 2 oz./ac. of Blanket 4F with 3 oz./ac. of Sonic or Authority First offers about the same amount of sulfentrazone as 5 oz./ac. of Sonic, but at a lower cost -- and this mix offers residual control of both waterhemp and giant ragweed. Thompson said, "As a rule of thumb, every 1 oz./ac. of Blanket will add approximately one week of additional residual control." Carlson added that there "is no additional benefit to go with the higher rate of Sonic for giant ragweed."
For a broader spectrum of control -- in the absence of giant ragweed -- growers can choose Blanket 4F on its own, or with a variety of other combinations, such as Blanket 4F tank mixed with Sencor, Dual, or Outlook (or their generic/private label versions). These options provide "two modes of action to control waterhemp and many other small-seeded broadleaves," said Thompson.

clean soybean field after Blanket 4F application
The photo at right, taken by last summer by Thompson in St. Peter, MN, shows soybeans (in a field with waterhemp and giant ragweed pressure) 50 days after a pre-emerge application of Sonic plus Blanket 4F at 3 oz./ac. each -- with no post treatment or burner product applied.
It's not too early to discuss tough weed control options for 2017. Contact your Federated Agronomist to design a program that fits your specific weed issues.
In This Issue
Quick Links
Corn Grower Workshops Start Feb. 20th
Federated's 2017 Corn Grower Workshops start on Mon., Feb. 20, and continue through Feb. 24. Each workshop, beginning at 10 a.m., will focus on the theme, Corn Economics and Agronomics, and will conclude with a free lunch. Contact your nearest  Federated location to RSVP and for details on specific venues for each meeting.
Workshop topics:
  • Economics x Agronomics
  • Liquid Fertilizer Starters
  • Biologicals
  • Gypsum
Monday, Feb. 20 -Osceola

Tuesday, Feb. 21 -Rush City

Wednesday, Feb. 22 - Ogilvie

Thursday, Feb. 23 -Albertville

Friday, Feb. 24 - 
Another Herbicide Labeled
for RR 2 Xtend Soybeans
Another herbicide label has been approved for use with the Roundup Ready 2 Extend ®   soybean system (dicamba tolerant soybeans).

Engenia herbicide, a BASF product, has been given a supplemental label for 2017 and 2018.

To learn more about this newly labeled product and how it can help in the battle against problematic weeds, contact your Federated Agronomist.
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Princeton, MN 55371-1941