From Beck’s 2023 Ohio PFR Results, the pictures above were taken from treatments 15 feet apart, three days after the Veltyma application was made. The anthers contain the pollen grains.

It’s not too early to take action: Minimize vomitoxin at harvest

By Luke Schulte, CCA, Beck’s Hybrids

The wide planting window throughout the state has led to a large variance in the growth stage of our corn crops. However, for some, fungicide season will be here before we know it.

Over the years, vomitoxin (VOM) in corn has become increasingly more common. Much of this is due to the increase of relative humidity levels post-pollination. Vomitoxin begins as gibberella ear mold. The causal pathogen, fusarium graminearum, is present to some degree in most all fields but is especially abundant in fields with a history of gib ear mold, fields with minimal air movement, and often corn after corn fields.

Infection primarily enters the ear via silk channels, particularly the straggler green, unpollinated silks remaining after pollen shed has concluded.

Infection primarily enters the ear via silk channels, particularly the straggler green, unpollinated silks remaining after pollen shed has concluded. The fungus will attach and grow down the silk to infect the ear. Anything that hinders pollination has the potential to impact gibberella/vomitoxin levels.

• Lack of accessible nitrogen by approx. V3/V4

• Heat throughout pollination

• Drought

•Insufficient nitrogen overall

Knowing successful pollination has a great deal of influence on vomitoxin, Beck’s conducted a study in 2023 evaluating the potential impact of fungicides on VOM, evaluating several fungicide products and application timings. While their team saw very minimal differences amongst fungicide products, they did realize timing was important. 

Fungicide products that contain either the strobilurin or SDHI classification of fungicide offer more than just disease suppression; they also provide stress relief to plants. However, this claim of increased stress tolerance has been hard to validate — until now.

By Beck’s observations, the Veltyma-treated corn had 30% to 50% of the anthers still clinging to the tassel, indicating pollination was still several days from completion, while the untreated corn had nearly concluded pollen shed. This is proof that fungicides (containing either strobilurin/SDHI) do, in fact, reduce ethylene production and, therefore, stress. This widens the pollination window and provides for more complete overall pollination. While many have seen the yield advantages of applying fungicide to corn, utilizing a fungicide to reduce VOM may require an adjustment to application timing.

In Beck’s 2023 Fungicide & VOM study, the only fungicide product applied both prior to tassel (V18) and at silking (R1) was Lucento. The first-year results look encouraging. Not only were VOM levels reduced (< 33%) by achieving more successful pollination, but a greater yield advantage was also observed with the earlier application versus the traditional timing of R1. Beck’s will be conducting this study again in 2024.

While the VOM levels were not zero at either application timing, it’s important to note the length Beck’s PFR team went to ensure vomitoxin was present within this study: 

  • Corn-after-Corn
  • Field with a history of VOM
  • Planted late (end of May)
  • Utilized a highly susceptible hybrid
  • Hand-inoculated the silks with the fungus causing VOM.

Considerations for an “early” fungicide application

  1. Target application timing approx. 4-5 days before to tassel
  2. Do NOT utilize an adjuvant containing NPE
  3. Drone application results have looked very promising (Reference pg. 165 of Beck’s 2023 PFR Book)
  4. Utilize a PFR Proven fungicide (Reference pg. 67-68 of Beck’s 2023 PFR Book)

While it’s only June, preparations now have the potential to make harvest not only more profitable, but more enjoyable as well.

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