Pennsylvania: Early Preplant Herbicides – How Early Can They Be Sprayed?

Pre-plant herbicide application. ©Debra L Ferguson Stock Photography

Pre-plant herbicide application. ©Debra L Ferguson Stock Photography

Historically, we have not recommended early preplant herbicide (EPP) application in our region with a couple of exceptions, such as for marestail control. In general, residual herbicides applied more than two weeks ahead of planting almost always require additional weed control often in the form of a post application.

With the adoption of Roundup Ready soybean and corn and now with Xtend, Enlist E3, and LLGT27 soybean varieties, there may be more opportunity to apply a residual burndown program two or more weeks ahead of planting with the idea of coming back with a well-timed post treatment.

A number of herbicide labels specify in days what is allowed EPP. Herbicide rates may increase for EPP, so consult a current herbicide label for specific use directions. The table below provides some spring EPP application intervals for some common corn and soybean products.

Table 1. EPP application intervals for selected herbicides.
A. Crop: Corn

Herbicide Spring preplant application
(maximum number of days ahead of planting)*
Acuron, Acuron Flexi 28
Anthem Maxx 45
Atrazine 30
Degree, Harness, etc. 30
Balance Flexx, Corvus 21 – 30
Hornet 30
Instigate 14
Lumax EZ, Lexar EZ 14
Dual 30
Princep 14
Resicore 28
Surestart II 30
Verdict, Sharpen 30
Valor, Fierce 30
Zidua 45

B. Crop: Soybean

Herbicide Spring preplant application
(maximum number of days ahead of planting)*
Anthem Maxx 45
Authority products 45-60
Canopy 45
Envive, Trivence anytime
FirstRate 28
Dual 30
Optill, Sharpen (2 oz/A), Verdict 30
Prowl 45
Prefix 15
Python 30
Sharpen (2 oz/A), Verdict anytime
Sonic anytime
Surveil 14?
Valor 14
Valor XLT anytime

* Maximum interval may specify that a sequential application is necessary.

Regarding some of the popular PPO/Group 14 soybean herbicides (e.g., Valor products, Envive, Fierce, Trivence, Authority products, Sonic, Surveil, others), if using these in combination with Sharpen/Verdict/OpTill/Zidua Pro for control of marestail, there is a 14-day restriction before planting.

So, if you tank mix Sharpen-containing products with another PPO/Group 14 residual herbicide (with the exception of Prefix) you must wait 14 days to plant soybeans. Or if Sharpen is applied EPP in a burndown mix without the PPO residual product, then you must wait 2 weeks before applying the Group 14 residual herbicide at planting.

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