Jordan Peanut Grower Magazine Column for May Peanut Notes No. 28 2021
The success we have in peanuts during the first month of the season can have a major impact on overall success of the peanut crop. A good start is critical. Whether it is reduced tillage or conventional tillage, starting clean is a must. This involves effective tillage or use of herbicides to make sure winter weeds and emerged summer weeds do not compete with emerging peanuts. For example, in our region there are growers that routinely have issues with dogfennel in reduced tillage and in some cases in conventional tillage. We do not have an effective herbicide to control this weed once peanuts emerge. High rates of glyphosate and a strong rate of paraquat are essential to control this weed prior to peanut emergence. Auxin herbicides applied at least a month before planting can help too, but making sure this weed is controlled when peanuts begin to emerge is a must. In some years with conventional tillage we run into problems with large weeds sneaking through our tillage operations. Palmer amaranth is an example of one of these weeds. If fields have good soil moisture, sometimes we do not kill all of these weeds with tillage, especially the larger ones. Applying a burndown herbicide even when you plan to till before planting can help prevent these weeds from escaping and creating an issue once peanuts emerge. It can make a big difference. Most Palmer amaranth plants are resistant to glyphosate, so a burndown rate of paraquat is in order prior to disking fields that have big pigweeds that can survive disking. Do whatever it takes to have a clean field when peanuts begin to emerge.
Make sure adequate stands are obtained by looking close at the germination percentage of seed and adjusting seeding rates accordingly. Five seed per foot of row is a good rate for Virginia market types in North Carolina. Error on the side of planting deeper rather than shallower. Peanuts can emerge from three inches or more, and deeper plantings can protect inoculants, used for biological nitrogen fixation (BNF), from excessive heat. If planted shallow, even with good soil moisture, soils can heat up to a point where liquid inoculants can be compromised due to high temperatures. Deep is better in general than shallow.
Be cautious about products applied in the furrow with seed. Make sure someone else has done it before you try it. If no one has done before you, and you can’t resist making a go at it, do so on a small scale first. Replanting or managing a peanut crop with a marginal stand is painful and financially risky. Outside of inoculant for BNF, insecticide for thrips control, and on rare occasion fungicide for control of seedling disease or CBR, there is minimal benefit (if any) to other products applied in the seed furrow. Velum and Velum Total have been shown to suppress nematodes in some peanut-producing states. In North Carolina, we have not clearly demonstrated a benefit from these products for nematode suppression. But we are doing more research on this in 2021. It is critical in North Carolina (and the V-C Region in general) to control thrips with systemic, in-furrow insecticides. While year-to-year variation can be observed, imidacloprid products, Velum Total, Phorate, and AgLogic adequately suppress thrips and protect yield. If tomato spotted wilt has been a major issue in your area, use caution with imidacloprid. In North Carolina, we generally have adequate variety resistance and relatively low incidence of spotted wilt, and this enables us to use imidacloprid with minimal risk for spotted wilt.
If we have a clean seed bed at planting (effective weed control), establish at least 4 plants per foot of row across peanut fields for Virginia market types, suppress thrips with in-furrow insecticides, and include inoculant at planting for BNF, we are well on our way to doing all we can to optimize peanut yield. Putting at solid PPI, PRE, and POST herbicide program in place is also critical during the first month of the season. Timeliness is key on all of these inputs. One more quick note of caution. In new ground fields it can pay to apply a peat-based product to seed in the hopper in addition to applying a liquid or granular inoculant in the seed furrow at planting. This is great insurance if something happens to delivery with a planter unit. I’m not sure if you will read this before you plant, but if you have zinc indices above 250 (North Carolina soil testing,) hit pause for a minute before you go any further. Higher soil pH can help overcome zinc but it is not a miracle. There is no correction for zinc toxicity.