Saturday, October 16, 2021

Minimize The Risk Of Valor Injury

Peanut planting in Georgia started in the southwest corner of the state the first week of April. But it slowed at mid-month with cooler weather. Based on conversations with consultants and county agents, most of the early planted peanuts look OK with only a few areas having issues with seedling disease.

Scott Monfort
University of Georgia

I mention this as a reminder to go back and visit all of the fields you plant within the first seven to 14 days to make sure you do not have any stand issues due to seed quality, seedling disease, moisture or unknown planter issues. Timing is extremely important in making effective replant decisions. The later you wait, the more yield potential you risk losing.

Another question we get is related to Valor. “Will I need to replant if I have Valor injury?” The answer is, “Not likely.” Peanut plants are pretty tough and almost always recover from this. To minimize Valor injury:

  • Plant high-quality seed (germ and vigor). Quality is always important. Know the percent germination of purchased seed.
  • Plant into good moisture and at a temperature that allows the seed the best opportunity to germinate and emerge quickly.
  • Plant at a depth of at least 1.5 inches. Planting shallower can increase the risk of germination problems and Valor injury.
  • Apply Valor no later than two days after planting. The risk of injury increases significantly the closer it is applied to peanut emergence.
  • Irrigate as soon as possible behind the Valor application for activation and to reduce injury. Injury can still occur after a hard rain during cracking and emergence, even though the field was irrigated after application.
  • Do not irrigate at cracking and emergence unless fields are hot and dry and need irrigation to ensure a good stand. Typically, the lack of moisture can result in more stand loss than that from Valor injury.

As an additional Valor-related item, unless absolutely necessary, do not put Gramoxone on peanuts that have significant Valor injury. If a peanut field was clean at planting and Valor and other preemergence herbicides were activated at planting, an at-cracking application of Gramoxone may not needed.


Check Your Zinc Number Before Proceeding

David Jordan
North Carolina State University

Starting clean is a must. This involves tillage or herbicides to make sure weeds do not compete with emerging peanuts. In our region, we have growers who have dogfennel, but 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 emerge is a must.

With conventional tillage, sometimes large weeds sneak through, especially if there is good soil moisture. Palmer amaranth is one of these weeds. 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. Most Palmer amaranth are resistant to glyphosate, so use a burndown rate of paraquat prior to disking fields that have big pigweed. Do whatever it takes to have a clean field when peanuts emerge.

Look at the germination percentage of your seed and adjust 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. Peanuts can emerge from 3 inches or more, and deeper planting protects the inoculant, needed for biological nitrogen fixation, from excessive heat. If planted shallow, even with good soil moisture, soils can heat up to a point where liquid inoculants can be compromised.

Outside of an inoculant, an insecticide for thrips control and the rare occasion of a fungicide for control of seedling disease or Cylindrocladium black rot, 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 states. In North Carolina, we have not clearly demonstrated a benefit from these products for nematodes but will do more research in 2021.

It is critical to control thrips with systemic, in-furrow insecticides. While year-to-year variation is observed, imidacloprid products, Velum Total, Phorate and AgLogic adequately suppress thrips and protect yield. If tomato spotted wilt virus has been a major issue in your area, use caution with imidacloprid.

Have a clean seed bed at planting. Establish at least four plants per foot of row across peanut fields for Virginia-market types. Suppress thrips with an in-furrow insecticides. Include inoculant at planting for biological nitrogen fixation. Do all these things to optimize peanut yield. Putting a solid preplant incorporated, preemergence and postemergence herbicide program in place is also critical during the first month of the season. Timeliness is key on all these inputs. One more quick note of caution. In new ground, apply a peat-based inoculant 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 the planter unit.

Lastly, if you have zinc indices above 250 (N.C. soil testing) hit pause before you go any further. A higher soil pH can help overcome zinc, but it is not a miracle. There is no correction for zinc toxicity.


Treated Seed Still Needs An In-Furrow Fungicide

Kris Balkcom
Auburn University

Well, it seems that I missed the weather prediction for April. I thought planting would start earlier since

Easter was the first week of the month and cool snaps would be over soon after. The cooler temperatures lingered on, delaying an early start. Hopefully May will provide consistent warmer temperatures to not slow down the crop. However, we make the best of the hand we are dealt.

A plus for this planting season is seed quality. Every germination report I have seen has been in the low 90% germination with a few around 85%. This is a far better starting point for achieving the stand we want. With this quality seed, there shouldn’t be as much replanting or filling in gaps this year. Even though you may feel like you’re late or behind, remember you are probably ahead of last year because of quality and not having to replant.

Apply an in-furrow fungicide at planting to help with seedling disease. Last year, we saw that treated seed still benefited from an additional in-furrow fungicide. Also be on top of weed control with preemergence herbicides. I have heard producers say preemergence herbicides hurt their stand, but this should not happen when planting high-quality seed.

Just in case there is a seed issue, be sure to visit planted fields in a timely fashion and take stand counts to verify if re-seeding is needed.


Rate Efficacy After Herbicide Applications

emi kimura
Texas A&M AgriLife
Extension Peanut Specialist

April in the Southwest was very dry with the drought monitor rating extreme to exceptional over the West Texas/New Mexico, South Texas, and south of the panhandle regions. The lack of moisture will be a limiting factor during planting. Under such uncontrollable weather conditions, well-planned planting preparation becomes important to improve stand establishment. Among those preparations, pay attention to seed quality (germination and vigor), seed storage, planting depth, soil temperature, planter setting and speed, inoculant application and storage, and preemergence herbicide application.

As we move into May, peanut acres are slowly being planted across the state. Remember that the best weed management strategy is to starts with clean fields. It is critical to use preplant burndown, preplant incorporated and preemergence herbicides to achieve this goal. Yields losses are minimized when peanuts are free of weed competition for the first four to six weeks after planting.

When applying early postemergence and postemergence applications, make sure that weeds are actively growing to absorb and translocate the herbicide for maximum efficacy. Other factors to consider when applying early post and postemergence herbicides include adequate spray volume for a good coverage, appropriate herbicide rates and the use of adjuvants. After herbicide applications, it is always a good idea to revisit the treated fields to rate the efficacy of herbicides applied and look for any potential herbicide-resistant weed populations in your fields.

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