Mark Loux wrote this piece on burndown in CORN.

He must have read my poke at Extension because he poked back at me.

"F)

Be cautious about adding any number of other products to glyphosate, because many of these contribute very little to the activity of glyphosate. Products in this category include:

Some of these products can cause the fairly rapid development of symptoms on weeds, usually contact-herbicide type injury, but this contributes little to the eventual control. Products that cause these symptoms can reduce the activity of glyphosate, especially when weeds are large. Exceptions to this would be where the product actually controls a weed well on it’s own, such as the activity of Aim or Resource on velvetleaf. Consider that none of the products listed above have much activity on giant ragweed, and they all have essentially no activity on emerged marestail. Bottom line – make sure you know what the purpose is for adding a product to glyphosate burndown treatments, and consider that increasing glyphosate rates is often much more effective than adding other products that have little activity on tough no-till weeds. "An incomplete list of products that won’t help glyphosate burn down big weeds in no-till soybeans - Mark Loux
The delay in soybean planting has resulted in continued questions about substitutes for 2,4-D ester in soybean burndown treatments. We covered this subject in the May 4 edition of C.O.R.N. As a quick reminder, the best bet for burndown in soybeans without 2,4-D ester is to increase glyphosate rates and add a product that contains chlorimuron or cloransulam. Also, use true ammonium sulfate instead of ammonium sulfate replacements, and make sure that adjuvant premix products that contain ammonium sulfate are supplying a high enough rate - 8.5 to 17 lbs/100 gallons of spray mix, depending upon how hard the water is. While glyphosate can be more active when applied in spray volumes of 10 gpa or less, higher volumes can be justified in fields with large and dense weed populations to ensure adequate coverage. Some dealers promote the use of additional nonionic surfactant to improve the activity of glyphosate. This has occasionally improved control in OSU research with certain glyphosate products. Most glyphosate products are formulated with surfactant, however, and increasing the glyphosate product rate also increases the surfactant rate.

Aim, Resource, Cadet, Valor, Spartan, ET, and 2,4-DB (also citric acid, WD-40, blue windshield washer fluid, and antifreeze)
The delay in soybean planting has resulted in continued questions about substitutes for 2,4-D ester in soybean burndown treatments. We covered this subject in the May 4 edition of C.O.R.N. As a quick reminder, the best bet for burndown in soybeans without 2,4-D ester is to increase glyphosate rates and add a product that contains chlorimuron or cloransulam. Also, use true ammonium sulfate instead of ammonium sulfate replacements, and make sure that adjuvant premix products that contain ammonium sulfate are supplying a high enough rate - 8.5 to 17 lbs/100 gallons of spray mix, depending upon how hard the water is. While glyphosate can be more active when applied in spray volumes of 10 gpa or less, higher volumes can be justified in fields with large and dense weed populations to ensure adequate coverage. Some dealers promote the use of additional nonionic surfactant to improve the activity of glyphosate. This has occasionally improved control in OSU research with certain glyphosate products. Most glyphosate products are formulated with surfactant, however, and increasing the glyphosate product rate also increases the surfactant rate. Aim, Resource, Cadet, Valor, Spartan, ET, and 2,4-DB (also citric acid, WD-40, blue windshield washer fluid, and antifreeze)

Coup and Hud should get a kick out of this, I know I did.

Ed