Here is another round of timely management tips from Clemson peanut specialist Jay Chapin.
Our earliest planted peanuts are over 45 days old and beginning to peg. The crop is generally under some stress from declining soil moisture, 100+ temperatures and recovery from herbicides. Gypsum is going out on time and the main issues are continued weed control and making the first leaf spot applications by no later than 45 DAP.
More on Bravo Situation
From calls I have had this week from a couple distributors, they are temporarily out of Bravo and a few folks don’t have Bravo or Tilt/Bravo needed for their 45 DAP application. They expect more to be shipped soon now that a major plant is “back in production”.
My suggestion when asked for a Bravo or Tilt/Bravo replacement at 45 DAP was an 8 oz rate of Provost based on “bang for buck”. It will handle leaf spot at that timing and also provides some early season white mold suppression. Then at 60 DAP rotate to an alternative to Provost such as a Bravo tank mix if available (with tebuconazole or Convoy) or else strobilurin /carboxamide chemistry (Abound, Evito, Fontelis, Priaxor).
Do I need leaf spot control yet in this hot dry weather?
Leaf spot is driven by periods of surface leaf moisture. We don’t have a lot of that right now, but I would categorically make a leaf spot application on all peanuts no later than 45 DAP under S. C. conditions. This is particularly important on short rotation fields (less than 2 years out of peanut production) or adjacent to fields that had significant leaf spot when dug last year.
Control of late leaf spot is all about preventing the disease from getting started for as long as possible. A timely, relatively low-cost preventative application early is worth more than two high dollar rescue treatments late in the season if we get in trouble. Even in the current weather pattern we have a 30% chance of afternoon thunderstorms this week – we want a fungicide on the plant before the leaves get wet once we get to 45 DAP.
Other “Dual Purpose” Fungicide Options
There are several other “dual purpose” fungicide options in addition to the ones I listed in my previous peanut bulletin (Abound, Provost, Fontelis) for both leaf spot and white mold control in the 60 – 90 DAP interval.
Evito (5.5 oz/ac) is a strobilurin fungicide (fluoxastrobin). We do not have as much experience with this product as with Abound (azoxystrobin) but in our tests it has been similar in performance to the 18 oz rate of Abound.
Quash is a triazole (metconazole) like Provost and tebuconazole (generic Folicur). It has performed well against white mold at the 4 oz rate but needs 1 pt of Bravo added for leaf spot protection.
More details on Evito and Quash + Bravo are given on pp 48-52 of the 2015 production guide.
Custodia is essentially a jug mix of tebuconazole (generic Folicur) and the active ingredient in Abound (azoxystrobin). At the labeled 15.5 oz rate, Custodia has the equivalent of the standard 7.2 oz rate of tebuconazole + 7.5 oz of Abound. That’s a good combination for soil disease, but won’t stand up to late leaf spot under South Carolina conditions. I would strongly suggest adding 1 pt of Bravo if Custodia is used.
Most of the questions this week are about tank mixes for controlling the “second flush” of weeds two weeks after paraquat applications. Usually it’s a mix of sicklepod, morningglories, and grass (Texas panicum, crabgrass, goosegrass, or signalgrass).
If the grasses present are mostly all crabgrass or signalgrass along with the sicklepod and MG, we’re relying on Cadre plus 1% oil and some 2,4-DB to help with large sicklepod, MG’s, and maybe a few unseen escape pigweed.
If a significant population of killable pigweed is also present, we have to add the Cobra or Blazer.
If Texas panicum and/or goosegrass are the main grass problems, we can’t rely on Cadre alone unless you catch them very small. The surest solution has always been to hit the grass with Select or Poast, then come back the next day or two with Cadre for broadleaves, but that’s not practical for most growers. Using higher rates of clethodim (Select, Arrow, etc.) in a Cadre tank mix can offset the fact that Cadre reduces grass herbicide efficacy. Even a 14 ounce rate of clethodim (2lb/gal formulation) is very cheap for saving a trip.
We can also add the Bravo to these tank mixes at 45 DAP timing.
Conditions for weed control are certainly not the best with 100 degree days. About the only suggestion is to spray as much as possible early in the day when weeds are under less stress and more susceptible.
From what I’ve seen, I would cease foliar Orthene sprays for thrips this week. Thrips populations have declined to the point that we’re probably causing more potential mischief with killing predators than good from thrips control.