Fungicide Timing 101

Jun 12, 2024


corn with tar spot
The best time for applying a fungicide on soybeans is coming soon: R1-R2 (beginning flower to full flowering). This is considered the best time for general plant health, according to Brad Hipsag, Federated ag sales rep at the Ogilvie location.
 
Application rate on soybeans is 15-20 gal./ac. Spraying with a high number of gallons per acre assures full plant coverage and canopy penetration.
 
Hipsag said that field disease history should dictate the number of applications. For fields with a history of white mold pressure, two fungicide passes are recommended – first at R1, and then at R3, with at least 14 days between the two applications. (Photo shows field with white mold later in season.)
 
On corn, fungicides should be applied at tasseling, VT stage. Again, application with high gallons per acre is recommended to get as much coverage as possible; 15-20 gal./ac. 
 
Although herbicides can be applied as early as V10 or as late as R2, fungicides see their best response when applied at tasseling “for general plant health,” said Hipsag.
 
Major tar spot (see photo) management in corn may require two applications, once at V10-R2, and it may be warranted later, at VT-R3, if the problem persists.
 
Hipsag noted that fungicides can help with other diseases besides tar spot, such as northern corn leaf blight, gray leaf spot, and rusts, all of which tend to show up later in the growing season.
 
Got questions about fungicide timing? Talk to your Federated Agronomist.

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