Some peanuts are just starting to bloom, so here are some timely remarks from Clemson Peanut Specialist Jay Chapin.
What I hear from our distributors is that they estimate getting anywhere from 60% to 100% of their chlorothalonil (Bravo) needs met, depending on who you talk to. The only certainty is that there is a lot of uncertainty about how much Bravo will actually be delivered as the season progresses, some think they will get all they need, some not.
We are rapidly coming up on our first leaf spot application by 45 DAP, and some Bravo has already gone out at a reduced rate (1 pint) rate in 35 DAP Cadre application.
What to Do?
I would not hesitate to use available Bravo (or Tilt / Bravo) on these first leaf spot applications and not worry about any substitutes until at least 60 DAP timing. Who knows, we may end up getting the Bravo we need later anyway, and we want to start off with the most reliable control we can get – control is all about prevention and not letting anything get started early in the year.
Once we get to 60 DAP the focus for the next four sprays shifts to combinations that will control both leaf spot and white mold. If Bravo is short, the question is whether to substitute another leaf spot material for Bravo in tebuconazole (generic Folicur) or Convoy / Artisan tank mixes, or to just go with a dual purpose product like Provost 8-10.7 oz, Abound 18 oz, or Fontelis 16 oz.
The potential leaf spot materials that could be substituted for Bravo in a tebuconazole or Convoy tank mix are Alto 5.5. oz, Stratego 10-14 oz, or Priaxor 4-6 oz. Headline (6-9 oz) is out of production, so would only be an option with carry over material.
Even though tebuconazole only costs $3/ac, adding a Bravo substitute for leaf spot often adds up to the same or even more cost than just going with one of the dual purpose products, especially given recent cost reductions in some of the older chemistry (Provost and Abound). All of the dual purpose products are at least as good, or even better than Alto or Stratego for leaf spot. Priaxor has shown superior leaf spot control in some tests.
Convoy is a reliably excellent white mold product, but absolutely needs a leaf spot material added. Either Bravo (1.5 pt) must be prioritized for Convoy tank mixes, or accept the added cost of a Bravo substitute. Artisan is the same white mold chemistry as Convoy but contains Tilt so only requires 1 pt of Bravo added.
Cutting Corners on Leaf Spot Control
Muscle ADV (2 pt) is tebuconazole (generic Folicur) with 1 pt equivalent of Bravo. It’s a good combination, but I would advise against consistently relying on Muscle ADV without adding the extra ½ pt of Bravo. I know it was done last year without getting into leaf spot trouble, but we get away with a lot on leaf spot control when it doesn’t rain a drop in August and early September.
With a potential shortage of Bravo and the increased cost of some of the alternatives there might be a tendency to reduce rates or stretch spray intervals beyond 14-15 days. That could be a lot more expensive in the end. We saw signs of reduced leaf spot control with both triazoles and strobilurins in some of our 2014 fungicide tests at Blackville. If anything we should be more cautious with our leaf spot programs. Maintain rates and spray intervals.
My oldest peanuts are blooming but my youngest peanuts aren’t quite three weeks old. Can I put gypsum on all of them? Yes. Blooming is perfect timing, but better a little early on some of them than a little late.
Lingering thrips injury to terminals is holding back growth and recovery from herbicide injury in some fields. If so, apply Orthene 8-12 oz. Orthene can be mixed with Cadre applications. Anything that delays ground coverage is a problem, especially on runners. The thrips stunting problems are primarily in Thimet fields due to erratic application problems with a granular. The liquid imidacloprid applications are more consistent.
The photo shows a row of peanuts that has been heavily stunted by thrips due to erratic Thimet application.
If Boron is going to be applied, the early herbicide applications (paraquat or Cadre) are a good opportunity to get it out of the way and avoid later tank mixes when we will be applying Mn with various herbicide – fungicide mixes. A single application of 0.25-0.4 lb Boron is adequate.
Herbicide Tank Mixes
As we begin to make our Cadre applications, there are always many questions about herbicide tank mixes with fungicides, surfactants, and nutrient additives. It’s impossible to cover all the combinations, but it might be helpful to give an example of what we have tank mixed: Cadre + Dual + Cobra (or Blazer) + 2,4-DB + Bravo + tebuconazole. That’s not a recommendation, merely an example of what has been used in a dire weed situation. If Dual was not included we would have added 1% crop oil for Cadre performance. Boron has also been added, but there are a lot of formulations, so read the label for any tank mix restrictions with boron products.
Example of what to avoid: Mn and 2,4-DB mixes. Poast or Select performance is generally reduced by tank mixes with other herbicides such as Cadre.
In a previous bulletin I mentioned the disease carryover and digging problems caused by volunteer peanuts. I failed to mention another important issue for buying points. If the volunteer variety is not high oleic and the new crop is, they will be contaminated by the volunteers.