From UGA Extension Plant Pathologist Dr. Bob Kemerait here are fungicide applications considering favorable wet weather, delays in applications, corn and peanuts in vulnerable growth stages:
“1. Corn growers with a pre-tassel crop or one already denting? Don’t spray.
2. Corn growers Macon and north- watch and wait.
3. Corn growers with a scout in the field and no southern corn rust- you can wait, but you might need to pull that fungicide trigger all of a sudden.
4. Sprayed within the past 2 weeks? Don’t spray today, but given the threat, you might need to spray again…
5. Sprayed 3 weeks ago? I’m glad you did; now check corn growth stage before you spray again.
1. Peanuts: leaf spot and white mold are a active. These first hits of white mold on young plants are near impossible to stop, but you CAN stop the spread.
2. “Bob, we’re 42 days out now without a fungicide, and it may be a week before we can get in the field. What’s do you recommend.”
A. Did you use Velum at planting? If so, it has helped you with leaf spot as well. Spray as soon as you can; wouldn’t hurt to include some fungicide with systemic activity. And something for early-season white mold as well.
B. If you didn’t use Velum, Thimet gave you a little help if you used it.
C. Bottom line: starting a spray program between 45 and 50 days after planting is tricky. My two top choices are use of Priaxor or Lucento. Second place would be Provysol + chlorothalonil, Alto + chlorothalonil, Domark + chlorothalonil, Mazinga, and even Aproach Prima. I’d also add 7.2 teb with them for good measure.
D. Can you mix Cadre with them? Yes. Can you mix clethodim with them? According to Dr. Prostko doing so will compromise your grass control so I wouldn’t do it.”