Flexstar GT 3.5 - Herbicide | Syngenta


Flexstar GT 3.5 Videos


Flexstar GT 3.5 Videos

Product Overview

Flexstar® GT 3.5 herbicide is specifically formulated to combat weeds that are difficult to manage with glyphosate alone, or are resistant to glyphosate and ALS-inhibitors. It contains 2 leading active ingredients and delivers 2 effective sites of action for use in soybeans and cotton. Flexstar GT 3.5 contains Isolink® II Technology, a unique adjuvant system designed to optimize the systematic activity of glyphosate and the contact activity of fomesafen. 

In soybeans, Flexstar GT 3.5 can be used as part of a full-season weed management system when applied as a follow up to Boundary® 6.5 EC or BroadAxe® XC herbicides.

Product Highlights

  • Combines 2 leading active ingredients, glyphosate and fomesafen
  • Utilizes the Isolink II Technology adjuvant system for improved effectiveness and reduced crop injury
  • Promotes the use of multiple effective sites of action and a system of overlapping residuals to help prevent or delay herbicide resistance when followed by Boundary or BroadAxe XC
  • Combats weeds that are difficult to manage with glyphosate alone



Colten Katz
Turon, KS

Colten Katz

“In terms of killing pigweeds, we found Flexstar GT 3.5 is by far your best option post-emergence in soybeans.”


Rick Johnson
Monee, IL

Rick Johnson

“On soybeans, we really like Flexstar GT 3.5 herbicide, which has helped us with the problems we’ve had with weed resistance.”




Download Supporting Flexstar GT 3.5 Documents

20189720183819515_Flexstar GT 3.5 Snip.JPG PDF
Flexstar GT 3.5 Sell Sheet(PDF)
20162282016526232834_soybean-herb-sell-thumb.jpg PDF
Soybean Herbicide Portfolio Sell Sheet(PDF)
20167572016315214512_Boundary-Flexstar.jpg PDF
Boundary-Flexstar GT 3.5 Sell Sheet(PDF)

Target Difficult-to-Control Weeds with Flexstar GT 3.5

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Flexstar GT 3.5 - Carousel, Chart
Flexstar GT 3.5 - Carousel, Chart
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This image series shows the superior weed management provided by Boundary® followed by Flexstar® GT 3.5 (right) vs. untreated (left) and Fierce® (center). Source: Syngenta, 2016.

The effectiveness of a strong full-season weed management program is even more apparent during bare ground trials, as shown here. Top left: No pre-emergence herbicide with a post-emergence application of Flexstar® GT 3.5. Top right: Envive® followed by Flexstar® GT 3.5. Bottom left: Valor® followed by Flexstar® GT 3.5. Bottom right: Boundary® followed by Flexstar® GT 3.5. Source: Syngenta Grow More™ Experience site, 2016; Kinston, NC.

One of the keys to weed resistance management is the use of multiple effective sites of action. The difference in weed control is clear when comparing a glyphosate-only application (left) to the 2 effective sites of action of Flexstar® GT 3.5 (right). Source: Syngenta, 2013.


Mar 6, 2018

Syngenta identifies key strategies to manage the spread of resistant Palmer amaranth

Syngenta warns that glyphosate-resistant Palmer amaranth, one of the most threatening weeds in Southern corn and soybean fields, continues to spread into the Midwest. Knowing how to defeat this tough weed is imperative to protect crop yields and manage future resistance.Read more »

Feb 20, 2018

Syngenta identifies key approach to protect yields from resistant giant ragweed

As corn and soybean growers continue the fight against weed resistance, Syngenta provides key insight into how to manage giant ragweed, a large-seeded broadleaf weed that truly lives up to its name.Read more »

Feb 15, 2018

Syngenta recommends overlapping residuals for season-long waterhemp management

Due to the expanding threat of resistant waterhemp, Syngenta urges corn and soybean growers to prepare a management strategy that includes overlapping residual herbicides with multiple, effective modes of action (MOAs) for the upcoming growing season.Read more »

Jan 16, 2018

Syngenta and university researcher offer key strategies for managing resistant weeds

In the battle against herbicide-resistant weeds, university and industry research has cast doubt on common assumptions and is rewriting some of the "rules" for managing resistant weeds.Read more »

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