I think at times we can focus too much on things that work or are successful rather than things that don’t work or just plain failed. The failures tend to sting a little more from a financial standpoint and aren’t soon forgotten and we tend to be more defensive the next year so it doesn’t happen again.
Above are pictures of two different hybrids in the same field planted every other 12 rows. Both were sprayed with fungicide. The hybrid that is healthy and green has huge potential. The hybrid that is brown and dead was infected by Tar Spot and it’s potential is probably 40-60 bu less per acre than it’s healthier counterpart planted alongside. Did the fungicide application fail? The answer is both yes and no. It’s likely that the healthy hybrid had both immunity and fungicide interaction that helped keep the plant alive even though the plant was probably already infected with the disease before fungicide was applied. The hybrid that did not fair so well probably did not have immunity towards the disease and the single pass of fungicide was not enough to fight the disease off.
Moral of the story to battle against Tar Spot is spray early and spray often to keep the plant healthy even though it may be infected with Tar Spot. Any fields that were sprayed at V-10 and then again at brown silk have no yield loss and remain healthy even though Tar Spot is present on the leaves.
So as we go into next year remember the failure in the above pic. There are a number of great hybrids out there with huge yield potential that are susceptible to Tar Spot. Don’t shy away from these hybrids just realize you may have to spray twice to see the big yields. For the hybrids that have an immunity towards Tar Spot one application may be just fine. Know what you’re planting and treat accordingly and you’ll have a successful 2024 crop year.