We don’t claim to know much about herbicides. The combinations are complex, and everyone has their favorites. We spend most of our time on learning about nutrients — especially foliar applied nutrients.
However, haven’t learned how to totally avoid herbicides in our test strips. This rainy spring is certainly one time when pre-emergence herbicides haven’t kept fields clean, especially in later planted soybeans.
Nor do we offer specific advice on what herbicide mixes to use. Our feedback from farmers does make us sure of one general rule: If you must spray a contact herbicide, WakeUP Summer is quite consistent in amplifying its effectiveness three ways:
1. It drops surface tension of the spray solution from about 70 dynes to somewhere around 30 dynes. That’s lower than the surface tension of most weed leaves. Thus, a spray droplet hitting a weed leaf spreads out and links up with other spray droplets. The spray mix gives the weed leaf a glossy coat. You don’t need a fine mist. We suggest a medium droplet size to reduce drift and evaporation.
2. It softens and lifts the waxy leaf cuticle on weeds, allowing active ingredients to penetrate quickly into the weed’s nutrient delivery network, the phloem tubes.
3. It acts as a carrier for chemical compounds. WakeUP is formulated entirely from plant-based oils, alcohols and other derivatives. Plant leaves easily absorb it, and the colloidal micelle structures created by WakeUP become lightly linked with chemicals via ionic bonding. The outside of each micelle is about 30 angstroms, or 30 billionths of a meter. This tiny micelle readily migrates into plant circulation and into individual cells.
Unless your herbicide label calls for use of an oil-based “sticker,” we suggest using WakeUP as the only surfactant in a herbicide mix. If the label calls for reducing the pH of the spray solution, we find that citric acid is most compatible with WakeUP. Spray grade ammonium sulfate will work, but WakeUP may precipitate out some of the sulfur into a few “creamy” floaters in the tank.
On June 27, we sprayed herbicide on a 10-acre patch of non-GMO soybeans which had been in corn in 2014. It’s rented ground with a history loaded with weeds. Our herbicide was Rhythm, a generic relative of Flexstar. Wind: calm in late afternoon. Temperature: mid-70s. Next day, a heavy shower came through. We used the 1.3 pint per acre rate of Rhythm which the label called for. Tank-mixed with a fairly heavy rate of WakeUP Summer: 8 ounces per acre. Our high-clearance sprayer was set to lay down 20 gal. of spray solution per acre, so the weed leaves were “clear coated.”
The next afternoon, here’s what a particularly weedy patch looked like:
Our farmer and consultant friends said that degree of burning in about 22 hours was possible under favorable conditions. What was a little puzzling was the lack of bronzing or burning on the soybeans.
So we watched the weed response another day. By the afternoon of June 29, lower stalks on most of the grasses had faded and it appeared that few weeds would survive. Here’s a sample of another weedy area:
When it finally gets dry enough to cultivate, the field should look pretty well cleaned up. We’ve been told that when you spray beans with Cobra, or Flexstar or Rhythm, you “should probably go on vacation for a week and not look at the beans… they’ll look fried, and take time to grow out of it.
However, these don’t look very stressed, two days after spraying. There’s some potassium deficiency because this is a low-potassium soil. But very little leaf burn.
Six days after spraying, weed control looked very effective. And there was little speckling or burning on beans, except for some curling at the edges of leaves. This is a photo from July 3:
We asked southeast Iowa farmer Keith Schlapkohl, one of our clients and a foliar spraying expert, his choice of postmerge weed control products. He mixes Cobra, Flexstar and Classic, all at a one-third rate or less. That brings three modes of action to bear on weeds, which is something the university weed specialists recommend to avoid or delay resistance buildup. Keith also adds Pinnacle where lambsquarters are a problem. On top of that, Keith typically spikes the spray solution with a little WakeUP Summer, and his water is treated with a reverse osmosis unit and a Pursanova structuring unit. All those enhancements help the active ingredients perform more consistently.
Keith also likes this combination because it tends to shorten the internode length on soybeans, improving standability.
Finally, here’s a wider view of that same field on July 5, 10 days after spraying. Dead weeds were cultivated from the middles.
Our only experience with Cobra herbicide was in 2014, when late weed escapes threatened to distort yield results in a few soybean test strips. We hit them with a labeled rate of Cobra, plus 5 ounces per acre of WakeUP Summer as the surfactant/penetrant. The photo below was taken about three days after spraying. It was puzzling not to see substantial soybean leaf damage.
We’ll defer to the herbicide experts on this subject. If we could manage it, we’d be like North Dakota farmer/rancher Gabe Brown: No herbicides, no insecticides. And no lenders to pay back.