Soil Residual Herbicide Options after Corn Emergence

Jun 01, 2020

By Amit Jhala

Application of soil residual herbicides is important because they deliver a few weeks of residual weed control and aid in weed resistance management by incorporating additional site(s) of action in herbicide program. Several residual herbicides can be applied after corn emergence without injury to corn. A Few important factors should be considered when addressing weed control with residual herbicides applied after corn emergence:

Corn growth stage,
Weed height, and
Tank-mix partner

Except some premix products such as Acuron, Harness Max, and Resicore with multiple herbicide active ingredients, these products generally do not have foliar activity and will not control weeds present at the time of application. Therefore, they should be tank-mixed with foliar active herbicides labeled in corn for control of existing weeds. Some of the herbicides, including Acuron, Anthem Maxx, Bicep II Magnum, Breakfree ATZ Lite, Degree Xtra, FulTime NXT, Keystone LA NXT, and Volley ATZ NXT contain active ingredients (such as atrazine) that has foliar activity. When applied at the correct weed growth stage, they will provide burndown activity (Table 1). Growers should consult product labels for additional information, such as the need for tank-mix partners or spray additives to improve control of existing weeds. For example, the post-emergence activity of atrazine can be increased by including an oil additive, yet additives should not be used if applying Balance Flexx or Corvus after corn emergence (Table 1).

Tank-mix partners may cause other effects regardless of the application timing. Follow application timing and other restrictions of tank-mix herbicide partner(s) as noted in the herbicide label. Table 1 has more specific information for residual herbicides that can be applied after corn emergence with regard to corn stage and weed height. Length and effectiveness of residual activity from in-crop herbicide application will vary depending on:

Weed species present,
Application rate of herbicide,
Rainfall or irrigation following application (minimum of 0.5 inch within a week of application is ideal to activate residual herbicide),
Density of the weed and crop canopy at the time of application, and
Length of subsequent weed germination events.

Figure 1 A & B. Corn at the two to three leaf stage in a field near Carleton, NE. Many residual herbicides can be applied after corn emergence. See Table 1 for more details.

Table 1. Corn growth stage and maximum weed stage when residual herbicides can be applied post-emergence.

Herbicide	Corn Stage	Maximum Weed Stage
Aatrex / Atrazine	0-12”	1.5”
Acuron	0-12”	3”
Anthem MAXX	V4	2”
Armezon PRO	0-30” Or V8	4”
Balance Flexxa	V2	1.5”
Bicep II Magnum / Cinch ATZ	0-12”	2-leaf
Bicep II Lite Magnum / Cinch ATZ Lite	0-12”	2-leaf
Bicep II Magnum	0-12”	2-leaf
Breakfree	0-11”	unemerged
Breakfree ATZ	0-11”	unemerged
Breakfree ATZ Lite	0-11”	unemerged
Callistob	0-30”	4”
Corvusa	V2	1.5”
Degree	0-11”	unemerged
Degree Xtra	0-11”	2-leaf
Dual Magnum	0-5”	unemerged
Dual II Magnum / Cinch	0-40”	unemerged
Expert	0-12”	6”
FulTime NXT	0-11”	unemerged
G-MAX Lite	0-12”	1.5”
Guardsman Max	0-12”	1.5”
Harness Maxx	0-11”	3”
Harness Xtra / Confidence Xtra	0-11”	2-leaf
Hornet WDG	0-20”	7”
Instigate	V2	3”
Keystone	0-11”	unemerged
Keystone LA NXT	0-11”	unemerged
Lumax EZ / Lexar EZ	0-12”	3”
Outlook	0-12”	unemerged
Prowl H2O	0-30”	1”
Python	0-20”	6”
Resicore	0.12”	2”
Resolve	0-12”	3”
Surpass NXT	0-11”	unemerged
Stalwart C	0-40”	2-leaf
Stalwart Xtra	0-5”	2-leaf
SureStart / TripleFLEX	0-11”	2” broadleaves
TopNotch	0-11”	unemerged
Warrant	0-30”	unemerged
Zemax	30” or V8	5”
Zidua	V4	unemerged

a If Balance Flexx and Corvus is applied after the corn has emerged; do not add crop oil concentrate.

b Injury may occur if Callisto is applied post-emergence to corn that has been treated with Counter. Do not tank-mix Callisto with any organophosphate or carbamate insecticide. Do not cultivate within seven days of application.

Source : unl.edu

Video: Why Seed Analysts are Thriving Under Seeds Canada

Last month in Edmonton, Alta., industry leaders and stakeholders gathered to discuss the evolving landscape of the seed industry at Seeds Canada’s annual conference. Among them was Sarah Foster, president of 2020 Seed Labs and the new vice-president of Seeds Canada.

Foster, who has been on the board of Seeds Canada for over a year, has witnessed firsthand the challenges and opportunities that come with the formation of the organization. Seeds Canada was established just over three years ago through the merger of multiple seed industry groups, including the Commercial Seed Analysts Association of Canada (CSAAC). Since then, the organization has been working to define its priorities and solidify its role in the industry.

“The challenge has been allowing the dust to settle after the merger,” Foster explained. “We’ve been focused on identifying what our priorities should be and ensuring that our members, especially the seed analysts, are getting what they need to continue their professional work.”

One of the recent highlights was a pre-conference event where the three major seed labs in Alberta — 20/20 Seed Labs, SGS Canada and Seed Check — opened their doors to members. The event saw a record number of seed analysts and business professionals in attendance. Foster emphasized the importance of this transparency, stating, “It’s crucial for people to see what goes on behind the scenes. We’re an open book now, and that openness helps build trust and understanding within the industry.”

The event also featured an environmental scan and a series of discussions that fostered strong communication among attendees. According to Foster, the dialogue was both encouraging and inspiring.

“A lot of people were really inspired by the fact that Seeds Canada is moving ahead with its agenda. The seed analysts, who have always worked diligently in the background, are now being recognized more prominently,” she said.

Before the merger, seed analysts were represented by CSAAC. Now, as part of Seeds Canada, they are finding their place within the larger organization. Foster believes that the integration has been successful, noting, “I think we’re thriving. You only need to look south of the border, where similar consolidations are happening.”

As Seeds Canada continues to evolve, Foster remains optimistic about the future. “I want to be totally transparent with anyone who is a seed analyst — I’ve got your back. We’re moving in a positive direction, and we’ll do everything we can to meet the needs of our members,” she said.