Here is a message from Dr. Bob Kemerait, UGA Extension plant pathologist. We are on the eve of May 1st and the most optimum time for planting peanuts is upon us. You can follow Peanut Rx through our UGA Peanut Team production guide, affectionately know by some, at least by me, as the “Huddle House Guide”, you can follow Peanut Rx online at peanutrx.org, and you can follow Peanut Rx on the back of prescription fungicide program cards from various companies to include Syngenta, BASF, Bayer, FMC, Nichino, Valent, CORTEVA, and others. Planting date is a key risk component in management of tomato spotted wilt disease. It is also a component in risk to leaf spot diseases and white mold.
There are four main considerations for in-furrow applications in a peanut crop in 2025 and the decision a grower makes, or doesn’t make can have season-long impact. Here are what I consider to be the Big 4 reasons for applications made in-furrow, much of which is important in my world of diseases and nematodes.
1. The first consideration is Rhizobium inoculant (Bradyrhizobium) to ensure that the peanut plants in the field are exposed to sufficient numbers of this nitrogen-fixing bacterium so as to have the root-nodulation needed to meet the nitrogen needs of the plant. We used to say that addition of inoculant is not needed if peanuts are planted at least once every three years in a field. While this still holds true, the use of inoculant as a matter of planting peanuts each year is seen as an “insurance” policy. Twenty-five years ago inoculants came in granule or powder form. Today most of our advanced formulations are liquids. Important to note, inoculants can be mixed or added to the open furrow with or at the same time as fungicides, nematicides, and insecticides without affecting efficacy of the inoculant.
2. Insecticides are applied in-furrow at-plant to manage thrips. As insects, management of thrips falls in the wheelhouse of Dr Abney. However, as thrips vector (transmit) the Tomato spotted wilt virus, they are important in my world as well. There are a number of products that can be effectively used in-furrow to manage thrips, to include Thimet, AgLogic 15G, Vydate CLV, and Imidicloprid. All of these products can be effective at managing thrips, I’ll leave it to Dr Abney to rank them, but Thimet stands alone in reducing risk to tomato spotted wilt disease. This is not to say than in a single trial here or a single trial there other products haven’t looked similar to Thinet. But over more than 25 years of research, Thimet and its active ingredient phorate, stand alone in reducing risk to spotted wilt. This has nothing to do with killing thrips and all to do with the serendipity (Dr Langston taught me that word) that Thimet activates natural defense mechanisms in the peanut plant to “fight” the virus. Can a grower get good control of spotted wilt disease without using Thimet? Of course the growers can, but they need to pay attention to other Peanut Rx factors, especially planting date and variety.
3. Peanut growers put products in-furrow to combat fungal diseases and to compliment fungicide seed-treatments. In-furrow fungicides are most often added as additional firepower against Aspergillus crown rot and Rhizoctonia. Note that our current seed treatments are already fighting those and other diseases, to include Rhizopus seed rot. Peanut growers do not always need to compliment the fungicide seed treatment with an in-furrow product. Several times this year I have asked you to ask the grower why he is using product “P” in-furrow. The common answer? “Bob, he says he has done it for years and is afraid to stop now.” Here are my thoughts- 1) putting azoxystrobin (Quadris, Abound, etc) is appropriate IF cooler and wetter soils favor Rhizoctonia. 2) if a grower is especially concerned about Aspergillus crown rot for whatever reason, a reduced rate of Velum (3 fl oz/A) can help (but is not sufficient for nematodes or for skipping a first leaf spot spray). If a grower is worried about CBR then he should apply Proline (5.7 fl oz/A) in-furrow. Proline in-furrow may give some early-season control of white-mold, but is more effectively applied for early season white mold control as a concentrated band 2-3 weeks after planting. Applications of Thimet, Velum, Propulse, and Proline all reduce early season risk to leaf spot diseases. Use of Velum (6.8 fl oz/A) Proline (5.7 fl oz/A) and Propuse allows grower to skip the leaf spot fungicide application timed for 30 days after planting.
4. Nematicides are applied in-furrow to fight the peanut root-knot nematode. AgLogic goes out at 7 lb/A and requires sufficient soil moisture for activation. Velum goes out at 6.8 fl oz/A and Vydate CLV goes out at 34 fl oz/A. Outreach, a new biological product from Valent is also available. Where root-knot nematodes punish peanuts in SW District, none of these products come close to protecting a peanut crop like planting a root-knot nematode resistant variety does.
