The following update was prepared by Clemson Peanut Specialist Dan Anco.
Some of the peanuts planted in April are starting to show their first blooms. In addition to signaling the start of the development of eventual peanut seed, bloom is also a reminder of when to apply calcium to the developing peanut crop. Large seeded runners (examples being TUFRunner 511, TUFRunner 297, and even 06G, FL-07 and 09B) and all runners grown for seed should receive 1000 to 1500 lb land plaster per acre. All Virginia types typically respond well to 1500 to 2000 lb land plaster per acre. See page 15 and 19 in the Peanut Production Guide for additional details. Foliar calcium applications are not recommended.
Most of the thrips damage at Blackville seems to have hit its peak and is now on the way out, with healthy new growth replacing older injured leaves. Thrips damage at our Florence test has increased a little since last week, with common insecticide treatments holding up fairly well. Most of the state can use more rain, which will help the canopies as they fill out and close the rows.
Tomato spotted wilt symptoms are just starting to show on a small number of leaves, but most TSWV infections have yet to reveal themselves. Below are two pictures showing ring-like symptoms. Seeing TSWV symptoms on peanuts lets us know if it’s there, but there isn’t much we can do once the peanuts are in the ground to further manage TSWV.
Fungal diseases, on the other hand, routinely require management actions throughout the growing season. For peanuts planted in mid-late April, the traditional 45 DAP start of the fungicide program is coming up. For moderate to low late leaf spot disease fields, this is generally 24 fl oz/A chlorothalonil (Bravo) or 24 fl oz/A Bravo + 7.2 fl oz/A tebuconazole (Folicur). If we are planting a highly susceptible variety like TUFRunner 511 or Georgia 13M, or if this is a field with typically higher amounts of late leaf spot disease (or if rotation intervals are shorter than at least two years out of peanut), we may consider more premium fungicides at 45 DAP, such as:
16 fl oz/A Bravo + 5.5 fl oz/A Alto
16 fl oz/A Bravo + 8-10 fl oz/A Topsin
32 fl oz/A Mazinga
4.3 fl oz/A Proline.
As a reminder from the county production meetings, Mazinga has no soil disease activity (not effective against white mold). Traditionally, the latest we should start leaf spot management has been 45 DAP, and the latest we should start soil disease management has been 60 DAP. We’re looking at a few things this year to see how much evidence there might be if we need to place more emphasis on earlier management, but for now the timeframes are the familiar ones. That being said, unless we are anticipating high soil disease risk, a 45 DAP fungicide application targeting only foliar leaf spots should probably be okay. If something like Mazinga that has no soil activity would be used at a later application (60 DAP for example), it would no doubt need a mixing partner in the tank, such as 16 fl oz/A Convoy, 4 oz/A Quash, or at a minimum, 7.2 fl oz/A tebuconazole.
Check with your buying point if you are considering products with propiconazole (e.g., Tilt Bravo, Stratego, Artisan). As with last year, peanuts treated with propiconazole may not be accepted for international import into the European Union. Peanuts treated with propiconazole are still okay for the green-peanut domestic market. Overall, the industry has decreased production of propiconazole products.