Not many could boast that this year was an easy growing season. Some growers have dealt with a wet spring, making it difficult to put in a crop, while others with a wet summer had a tough time applying post-emergence herbicides.
Others decided not to use preemergence residual herbicide and were not able to put on postemergence herbicides in a timely manner. As a result, some of the weeds may have gotten away from us.
If you are in this situation, no need to raise your hand, you might be thinking about using a harvest aid on that woolly field. There are a few herbicides that can be used up until the tasseling stage in corn, but most of the corn in Indiana is now at the tasseling stage or more advanced. So we're now limited to herbicide treatments that can be applied just prior to harvest to help dry down weed vegetation prior to a killing frost.
Harvest aid herbicide treatments can help in the drying down process at harvest. In these cases the corn or soybean might be ready to harvest, but the pesky weeds are not.
Harvesting green weeds with your crop can make for a trying day with the combine. No body enjoys digging green burcucumber or morningglory vines out of the header as the sun sets and when forecasted rain is on the mind. The following herbicides are labeled to be used as harvest aids.
All harvest aid applications have to be applied after the crop has matured. This is after hard dough or when soybean has dried down (brown pods or 30% grain moisture).
Aim EC [2 lb ai/gal carfentrazone] – Aim can be used as a harvest aid at 1 to 2 fl oz/A in corn and small grains; and 1 to 1.5 fl oz/A in soybean, no earlier than 3 days before harvest. Keep in mind that if you have used Aim previously this year when considering using it as a harvest aid, it can’t total above 2 fl oz/A in corn for the season. Aim can aid in the dry down of velvetleaf, morningglory, pigweeds and others.
Apply with a surfactant such as a non-ionic surfactant (NIS) at 0.255%v/v or a crop oil concentrate (COC) at 1 to 2% v/v. A nitrogen fertilizer such as UAN or AMS can also be added to the application. Use a minimum of 10 GPA with ground equipment and at lease 5 GPA with aerial applications to assure coverage.
Rage D-Tech [0.13 lb ai/gal carfentrazone + 3.93 lb ae/gal 2,4-D] – Rage D-Tech is Aim with 2,4-D to aid in the desiccation process. It can be used to help in drying down velvetleaf, morningglory, ragweeds, pigweeds and others in corn or small grains. Rage D-Tech does NOT have a soybean harvest aid label.
Rage D-Tech can be applied at 16 to 32 fl oz/A, but like Aim, no less than 3 days and 7 days before harvesting field corn or small grains, respectively. If used previously that year the total maximum amount of Rage D-Tech is 32 fl oz/A in a year. Apply with NIS (0.25% v/v), COC or MSO (1 to 2% v/v). Do not let meat animals graze on treated plants for 14 days after application and do not feed treated straw.
Roundup Powermax [4.5 lb ae/gal glyphosate] – There are several glyphosate products that are labeled for use as harvest aids. This information is based on the Roundup Powermax label. If you are using a different glyphosate product please see your specific product’s label for rates and use restrictions. Apply up to 64 fl oz/A with ground equipment or up to 44 fl oz/A by air when the corn has reached maturity (black layer) at 35 percent grain moisture or less. Apply as a harvest aid to soybean up to 3.3 qt/A when soybean are mature, after pods have set and lost all green color.
Do not harvest for feed or graze treated soybean for at least 45 days after application. Applications have to be made at least 7 days before harvest for both field corn and soybean. Use of glyphosate as a harvest aid is a good method to go after perennial weeds such as pokeweed and Canada thistle.
Gramoxone Inteon [2 lb ai/gal paraquat] – Gramoxone Inteon will provide fast dry down of weeds in corn and soybean. Apply at 1.2 to 2 pt/A to corn that has matured, after black layer, at least 7 days before harvest. Soybean harvest aid applications are different for varieties.
Apply to indeterminate soybean varieties approximately when 65% of the seed pods have reached a mature brown color or when seed has a moisture of 30% or less. For determinate varieties, apply when at least a half of the soybean leaves have dropped and the rest of the leaves are turning yellow. For both corn and soybean add NIS at 0.25% and COC at 1% v/v.
Do not harvest corn for at least 7 days after application. Do not harvest soybean for at least 14 days after application. Mature lambsquarter and cocklebur are tolerant to paraquat and may not dry down completely.