How To Kill Volunteer Corn In Soybeans

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Management of Volunteer Corn in Fields Affected from Derecho

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Downed corn from the August x Derecho, which affected millions of acres in Iowa, will contribute to pregnant volunteer corn populations in crop fields in 2021. Volunteer corn ranging from 800 to thirteen,000 plants per acre can crusade yield losses upwardly to 54% in soybean and up to xiii% in corn, according to the research conducted at SDSU, UMN, and UNL. In unharvested corn fields, establishment of one% of the corn seed nowadays would effect in volunteer corn populations of more than than 100,000 plants per acre. As well crop yield losses, volunteer corn can increment the severity of corn rootworm and diseases. Therefore, it is of import to develop proactive plans to control volunteer corn starting this fall.

Fall management: Much debate exists over the use of cultivation or no-till to manage volunteer corn populations. Fall tillage operations to size residue in Derecho-affected corn fields tin can potentially increase the soil-seed contact and promote formation of corn seeds this fall. This strategy will expose emerged corn seedlings to winter kill, thereby assistance in mitigating volunteer corn in the following year. Any seed that is not incorporated into the soil and left on the surface is less likely to germinate due to lack of soil-seed contact and vulnerability to seed predation/decay.

Ingather rotation: From a direction standpoint, the best option for storm-damaged corn fields this year would be to rotate to soybean adjacent year. Control of volunteer corn is easier in soybean compared to corn considering a number of Group 1 herbicides are labeled for use in soybean (Tabular array i).

Preplant options in the spring: Non-selective herbicides such as Gramoxone SL (paraquat) can be used to impale volunteer corn (Roundup Ready/Freedom Link) before soybean planting. Shallow spring tillage (field cultivation) can kill emerged volunteer corn, only it will also move corn seeds into the soil causing emergence of volunteers later in the season. Delayed planting in fields with the potential for high volunteer corn populations will let much of the seed to germinate prior to planting, therefore reducing populations that need to be dealt with after ingather institution.

Direction in soybean: Beneath are the list of Group 1 grass herbicides (Accase inhibitors) that can be used to control corn volunteers in soybean.

Product	Rate/acre
Select Max 0.97EC	6-12 fl oz
Clethodim 2EC	4-vi fl oz
Assure 2/Targa 0.88EC	iv-viii fl oz
Fusilade DX 2EC	4-6 fl oz
Poast	12 fl oz/a

To reduce early on-season crop competition, it is recommended to apply these products when emerged volunteer corn is 12 inches or less. Consult the product label for appropriate adjuvants (NIS, COC, MSO) to enhance the action of these products for controlling volunteer corn in soybean.

Fields that were planted to Roundup Ready only or conventional corn can be planted to LibertyLink, stacked LibertyLink + Roundup Ready hybrid, or Enlist E3 soybean in the next spring as Liberty provides effective control of volunteer corn. Two applications of Liberty, each of 32-43 fl oz/acre, are recommended in LibertyLink soybean. Group one grass herbicides (Tabular array one) volition be the but option for decision-making volunteer corn in Roundup Ready or Roundup Ready 2Xtend soybean.

Management in corn: If a Roundup Set merely corn was planted this season, switching to LibertyLink or stacked LibertyLink + Roundup Prepare hybrid would be an option for 2021. Liberty can be used to command Roundup Gear up volunteer corn. 2 applications of Liberty, each of 32-43 fl oz/acre, can be made in LibertyLink corn.

If the previous year'southward corn was Roundup Set + LibertyLink hybrid, Enlist corn tin be a viable pick to consider. Enlist corn is a new trait with stacked resistance to 2,iv-D choline, glyphosate, and 'fop' grass herbicides. Clinch Ii (quizalofop-p-ethyl) is the only grass herbicide labeled to command volunteer corn in Enlist Corn. It tin be practical at five to 12 fl oz/acre in Enlist Corn for selective command of Roundup Ready + LibertyLink volunteer corn. Assure® II should include COC (1% v/v) or NIS (0.25% v/5) and should be applied to corn at V2 through the V6 stage.

Overcoming grass herbicide antagonism with broadleaf herbicides: For in-season weed command, grass herbicides listed in Tabular array i are often tank-mixed with broadleaf herbicides, which may cause antagonism leading to inadequate control of grasses, including volunteer corn in soybean.

Figure 1. Percent volunteer corn control with clethodim (Select Max) and quizalofop-p-ethyl (Clinch Ii) practical alone or tank-mixed with dicamba. Adapted from Underwood et al. (2016). All treatments were practical at the V3-V4 stage of soybean to four to 5-leaf corn volunteers.

Antagonism by and large can be avoided by applying a college rate of the grass herbicide in the tank-mix or applying the grass herbicide 1 or more than days earlier or seven days after the broadleaf herbicide. In Figure ane, increasing the rate of clethodim or quizalofop-p-ethyl from 0.02 to 0.04 lb ai/acre overcame the decreased control of volunteer corn from adding dicamba (broadleaf herbicide) to the tank. In a research conducted at NDSU (Rich Zollinger), addition of adjuvants did non overcome the antagonism of clethodim with dicamba, except for AMS which is NOT labeled for use with Xtendimax or Engenia products.

Disclaimer: This article is for education purpose only. Mention of a specific product should non be considered as approval, nor should failure to mention a product be considered disapproval. Read the product label before using any herbicide.

Source: https://crops.extension.iastate.edu/blog/bob-hartzler-meaghan-anderson-prashant-jha/management-volunteer-corn-fields-affected-derecho

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