When 2+2 adds up to more than 4

Published on: 14:57PM Oct 20, 2009
Gordon Vail
If you’ve taken an applicator test, you probably remember that 2+2 doesn’t always equal 4. Sometimes 2 quarts of one product plus 2 quarts of another may antagonize each other and give you only 3 quarts worth of activity on a weed. But more often, you likely choose products where 2 quarts of one and 2 quarts of another create 5 quarts worth of activity.
That synergy is what happens when you combine mesotrione and atrazine, two effective herbicide modes of action that have a unique synergy. The broadleaf control received from the combination is better than the control expected based on each herbicide applied alone. The picture shows a bare ground study in Missouri taken 40 days after treatment with a combination of mesotrione and atrazine, showing the strength of long-lasting residual broadleaf control from the combined herbicides.
In the field, this synergy provides better control of glyphosate-resistant or glyphosate-tolerant broadleaf weeds like lambsquarters, waterhemp, pigweed species and ragweed.