Posted June 26, 2018


Late Herbicide Applications in Corn

With warm weather, corn growth takes off, and the question becomes, “how late can we apply certain products”. If you remember your parents saying that “nothing good happens after midnight”, the same can typically be said for herbicide applications after V8. Typically, you have a situation that is trying to rectify something that went wrong earlier and it is almost always too little too late. The reason late vegetative herbicide applications typically don’t work is because

1.) The corn is typically too big to allow the herbicide to penetrate the canopy and to actually get to the soil surface or the weeds

2.) The weeds are too big to be controlled by herbicides available at that stage of growth and

3.) There is the real possibility of affecting ear development with the use of the adjuvants needed for late growth stage herbicide applications.

Here is a cropwatch article from a few years ago that points to some of the same issues with late applications in corn: 

Below lists the latest growth stage you can apply common BASF Corn herbicides.

Armezon® / Armezon PRO®: DO NOT apply after V8 growth stage

Outlook®: Up to 36” tall corn
Prowl® H20: Up to 30” or V8 corn whichever comes first
Status®: 4-36” tall corn (V2-V8) No Drop Nozzles!
Zidua®: Up to the V4 growth stage

Last Weed Control with Engenia In Soybeans

For those of you planning to apply Engenia herbicide into your Dicamba Tolerant soybeans, remember to check the soybean growth stage before applying. Engenia herbicide can only be applied to soybeans up to and including the beginning bloom stage (R1). When soybeans reach R2 (when a flower is located within one of the two uppermost nodes on the main stem), Engenia herbicide can no longer be applied in that field. Also don’t forget to check for approved tankmix partners before your last application.

Engenia is a US EPA Restricted Use Pesticide. Additional state restrictions may apply. Always read and follow label directions. Engenia is a registered trademark of BASF Corporation.

Still time for Priaxor® Pre-Tassel in corn

Whether or not you have passed the window for herbicide applications, does not mean that we can’t still apply fungicides to our corn fields. All corn fields have the potential to benefit from an application of a fungicide prior to tassel, followed by a tassel or post tassel application (more on that in the next segment). Pre-tassel applications provide disease protection and increased plant health for your fields. Strong root development is crucial with early apps for future water and nutrient utilization. Applications of Priaxor can continue past V8, you just need to remove the adjuvants once we pass that stage of growth. Most ground rigs can easily make application on corn up to 48” tall. Pre-tassel apps can also be applied aerially or through chemigation units. Below is a slide from our 2015 results of a field near Archer, NE that shows the increased root development, kernel fill to tip of the ears and higher yield response of Priaxor being applied at V10.