So much for an early spring! Even though the calendar shows it’s April, mother nature appears to be stuck in January. Spring will eventually get here at some point, and its important to take this time to insure you have everything you need when planting arrives. At least in most of central Illinois the cold weather seems to have put a damper on the growth and development of many winter annual weeds. Even if your fields look clean from the road, closer examination might reveal there’s more weed pressure out there then you think, so be vigilant! If this is the case, it’s important to not skimp on your burn down ahead of either corn or beans especially if weeds, like marestail are present. For corn, I usually like to use products such as dicamba, glyphosate, sharpen, and atrazine to provide burndown of most winter annual weeds. Most of my programs in the past consisted of premix’s that contained atrazine (Bicep II Mag, Harness Xtra) spiked with 24-32 oz. of a 5 lb glyphosate. If marestail was an issue, I always advised my growers to throw a pint of dicamba into the mix to insure good control. Sometimes you could survive with 8 oz. if the marestail was less than 4 inches. The issue with dicamba is crop safety. Rain water can flush dicamba down into the furrow causing damage to the seed. Always make sure corn is planted at least 1.5 inches deep and the furrow is completely closed if you plan to use any dicamba product. I personally like to use Diflexx (Bayer) which is dicamba plus a safener to reduce the potential for crop injury. I especially like to use Diflexx when dealing with low organic matter sandy soils where dicamba injury can be of great concern.
Another product I’ve used to help with my burndown is Sharpen. Sharpen gives a faster burndown then dicamba or glyphosate and gives good residual, particularly on large seeded broadleaves like giant ragweed. Sharpen is excellent on weeds such as marestail and other annual broadleaves but lacks activity on grass. Sharpen needs to be applied in a spray volume of at least 15 gallons because it is a contact herbicide. Verdict is a pre emerge product that contains Sharpen and Outlook. I like this product because you get the burndown activity with the Sharpen and the residual capabilities of Outlook and Sharpen. One last note on Sharpen is always make sure it is applied before corn emergence!
Other alternatives that could be used are Gramoxone, Callisto, and Liberty. I only use Gramoxone in situations when a quick burn is needed. Gramoxone needs warm weather to be most effective and as a contact herbicide, needs to be applied in spray volumes of at least 15 gallons. I’ve also seen good results running Callisto (Mesotrione) with my burndown particularly when henbit is an issue. While I’m not a huge fan of Callisto and other group 27 herbicides pre-plant (I’d rather save them solely for the post trip), I do think they have their place and can be very effective burndown products. Callisto and other group 27 products can be found in premix’s of Resicore (Dow), Corvus (Bayer), and Acuron (Syngenta). If I’m adding Callisto to my burndown, it’s typically at a rate of 1.5 oz. with 1-1.5 lbs of Atrazine and 3 pts of Gramoxone. I ran this program on a couple farms last spring and was impressed with the results. If Callisto or another group 27 herbicide is already premixed into the product, I usually advise not adding anymore.
Liberty can also be used as an option, but spray coverage is the key. I only like Liberty when combating weeds less then 4 inches. Anything taller then 4 inches makes me nervous particularly when dealing with marestail which has a lot of growing points.
These are the programs I have ran on my customers over the last couple years for burndown options in corn. If you still need to finalize your chemical plans please give us a call, we would be happy to help. I will provide information on what I’ve used as soybean burndown options soon. As always make sure you read the herbicide label for proper adjuvants, mixing instructions, and crop rotation intervals. I will post more about those topics in the future. If you have any questions or concerns, please contact our office or myself. Thank you for you continued business and support.
Central Illinois Sales Manager