The derecho left many Iowa farmers with vital volunteer corn this rising season, and sadly some could also be dealing with the same scenario for 2022 after late August storms flattened fields.
Whereas corn killed throughout early reproductive levels, the kernels could not survive the winter nicely, corn killed throughout or after the R5 development stage, the kernels usually tend to survive the winter and be viable to germinate subsequent rising season. Losses of just a few bushels per acre can lead to vital volunteer corn populations. Volunteer corn starting from 800 to 13,000 vegetation per acre may cause yield losses as much as 54% in soybean and as much as 13% in corn, in accordance with analysis performed at SDSU, UMN, and UNL. In addition to yield losses, volunteer corn can permit corn rootworm and corn pathogens to persist and trigger points to corn in future years. It is very important develop plans to manage volunteer corn beginning this fall.
Know what you grew: One of many largest challenges for 2021 was figuring out whether or not planting corn was an inexpensive determination in fields with vital harvest losses or unharvested corn. The best choice for many storm-damaged fields is to rotate to soybean subsequent yr. Going again to corn subsequent yr is possible solely in fields the place a herbicide choice, like glyphosate or glufosinate, exists to kill volunteer vegetation.
Fall administration: A lot debate exists over the effectiveness of tillage in managing volunteer corn. Whereas fall tillage operations to dimension residue could enhance seed-soil contact and promote germination of corn seeds this fall, any seed left on the floor is much less more likely to germinate because of lack of soil-seed contact and vulnerability to seed predation. For some farmers, grazing fields or baling some crop residue is an choice that may assist cut back volunteer corn in fields with vital lodging.
Preplant choices within the spring: Tillage or non-selective herbicides, comparable to Gramoxone SL (paraquat), can be utilized to kill volunteer corn that emerges earlier than crop planting. Merchandise containing clethodim can be utilized previous to planting corn, however there’s a strict fee limitation and 6 day replant interval because of the potential for corn damage. If typical corn was grown this yr, glyphosate can be an extra efficient burndown herbicide. Whereas preplant tillage can kill emerged vegetation, it can seemingly break up ears and stimulate corn germinatation and emergence. Nearly all of volunteer corn will emerge after crop planting within the spring.
Administration in 2022 soybean: Desk 1 lists Group 1 grass herbicides (ACC-ase inhibitors) that can be utilized to manage corn volunteers in soybean.
To cut back early-season crop competitors, it is suggested to use these merchandise when emerged volunteer corn is 12 inches or much less. Seek the advice of the product label for applicable adjuvants (NIS, COC, MSO) to boost the exercise of those merchandise for controlling volunteer corn in soybean.
Fields that will probably be planted to a soybean selection with glufosinate tolerance will be handled with Liberty to manage volunteer corn if the corn grown in 2021 was typical or Roundup Prepared solely. Two purposes of glufosinate (32-43 fl oz/acre) are really helpful in LibertyLink soybean. Group 1 grass herbicides (Desk 1) would be the solely choice for controlling volunteer corn in soybean if the 2021 corn hybrid was tolerant to each glyphosate and glufosinate.
HG1 antagonism with broadleaf herbicides in soybean: The largest lesson realized from 2021 is the dramatic discount in efficacy that tank combine companions like 2,4-D (Enlist soybean) and dicamba (Xtend/Xtendflex) soybean can have on HG1 merchandise (Determine 2). Antagonism typically will be decreased by making use of the next fee of the grass herbicide within the tank-mix or prevented by making use of the grass herbicide a number of days earlier than or 7 days after the broadleaf herbicide. Because of antagonism points, many derecho-affected fields required an extra POST move containing solely a Group 1 product in 2021.
Administration in 2022 corn: If a Roundup Prepared solely hybrid was planted this season, switching to LibertyLink or stacked LibertyLink + Roundup Prepared hybrid can be an choice for 2022. Liberty can be utilized to manage Roundup Prepared volunteer corn. Two purposes of Liberty, every of 32-43 fl oz/acre, will be made in LibertyLink corn.
If the earlier yr’s corn was Roundup Prepared + LibertyLink hybrid, Enlist corn could also be an choice for some farmers. Enlist corn consists of stacked resistance to 2,4-D choline, glyphosate, and ‘fop’ grass herbicides. Guarantee II (quizalofop-p-ethyl) is the one grass herbicide labeled to manage volunteer corn in Enlist Corn. It may be utilized at 5 to 12 fl oz/acre in Enlist Corn for selective management of Roundup Prepared + LibertyLink volunteer corn. Comply with label suggestions for timing and applicable adjuvants.
Within the unlucky case the place lodged corn creates a major potential for 2022 volunteer corn, placing a plan in place now whereas 2021 corn hybrid data continues to be recent on the thoughts will assist cut back the inconvenience of this concern in 2022.
Supply: Iowa State College, which is solely accountable for the knowledge offered and is wholly owned by the supply. Informa Enterprise Media and all its subsidiaries should not accountable for any of the content material contained on this data asset.