Crop & Pest Report

Accessibility


| Share

Crop Safety from Products with Same Mode of Action (5/18/17)

Question: If I apply a soil-applied herbicide containing the active ingredient mesotrione (Callisto – Group 27) to my corn pre-emergence, can I follow with a post-application of Laudis (tembotrione – Group 27)? Will the two group 27 herbicides “overlap” on soil residual and cause crop safety issues or rotation restriction issues if used at labeled rates?

Crop Safety from Products with Same Mode of Action

Question: If I apply a soil-applied herbicide containing the active ingredient mesotrione (Callisto – Group 27) to my corn pre-emergence, can I follow with a post-application of Laudis (tembotrione – Group 27)? Will the two group 27 herbicides “overlap” on soil residual and cause crop safety issues or rotation restriction issues if used at labeled rates?

Answer: Both mesotrione and tembotrione are in the triketone chemical family and both active ingredients affect plants at the same site of action. This may seem logical that there could be an additive effect. However, with multiple applications of HPPDs made in previous years and no carryover reported this would suggest that both active ingredients are rapidly degraded in the soil and in corn plants. Laudis also contains isoxadifen safener which also adds a high degree of safening to corn plants. This answer is specific to these two herbicides and cannot be extrapolated to other herbicide combinations. Follow the crop rotation guidelines of both herbicides without an additive effect.

Another and more relevant issue is if a pre and post application of two different HPPD inhibitor herbicides will result in greater selection pressure and an increased risk of herbicide resistance weeds. The two applications of HPPD-inhibitors used on the same crop in the same season should be combined with other herbicides from different sites of action that are also effective against the target weed species.

Rich Zollinger

Extension Weed Specialist

Creative Commons License
Feel free to use and share this content, but please do so under the conditions of our Creative Commons license and our Rules for Use. Thanks.