• Corn products yield response to fungicide applied at the R1 growth stage varies. Understanding which corn products to target with fungicides should help ease management decisions by growers.

• This trial helped determine the magnitude of yield response from individual corn products.

• An early relative maturity (RM) (less than or equal to 103 day RM) corn product replicated trial was established in Mason, Michigan and a late RM (greater than 103 day RM) corn product trial was established in Colon, Michigan. 

• Specialty Hybrids™ brand corn products for Michigan were selected by local agronomists.

• The trial in Mason was a split-plot design with three replications with hybrid as the whole plot and fungicide as the sub-plot. This location received rainfall without irrigation. 

• The trial in Colon was an irrigated strip trial with a single replication.

• An application of Delaro® Complete Fungicide (10 oz/acre) was made on 7/13/21 in Mason and 7/14/21 in Colon at the R1 corn growth stage using a high-clearance sprayer with 20 gal/acre of water as carrier.

   

• Below average rainfall was received until late-June and then near-normal for the remaining season in Mason.

• Moderately high tar spot pressure was present in Colon and moderate pressure in Mason. The heightened pressure is Colon could be explained by the presence of consistent irrigation moisture. 

• Corn product response to fungicide can be variable. The lower yield differences of 39D389 brand blend and 39G569 brand blend compared to the untreated control demonstrate corn product response variability to fungicide application (Figure 2).  
  
  

• The average yield advantage to an application of Delaro® Complete Fungicide at R1 was 13 bu/acre.

• Fungicide applications tend to result in a yield increase; however, select corn products demonstrated a greater yield benefit from the fungicide.

• Management practices should first target corn products with the greatest response for fungicide applications.

6026_R1