Peanut Pointers: April 2024

AU-NPL 17 Helps Spread Risk

Planting season is just around the corner, and I feel that we might be able to get an earlier start this year as opposed to past years since Easter is earlier and we seem to be warming up nicely. I don’t want you to forget about Peanut Rx and soil temperatures. Always consider the three-day, four-inch average soil temperature with the extended forecast in mind. This higher temperature will ensure you better germination and a healthier start for your crop.

Also consider if you are planting early, be sure to use insecticide for thrips. Now the use of an insecticide alone doesn’t get you out of the woods when trying to prevent Tomato Spotted Wilt Virus. Use a variety more resistant to TSWV when starting to plant in the early season. Then transition to the lessor-resistant varieties later during the planting season. Also, if you are a smaller-acreage producer and can plant your crop relatively quickly, wait at least until the May 7-10 planting window. In years past, May 7-15 has been a more optimal time to plant to reduce TSWV pressure and have higher yields.

I know some producers were disappointed with the grades last year from AU-NPL 17, to the point they said they would not plant it again. Let me say that I know AU-NPL 17 will never grade as high as Georgia-06G. Therefore, when we had the drought last year, which stopped the maturity of that variety, it hurt us worse because the hulls were even thicker at a higher percentage than normal. This killed the grade right off the bat. I don’t know a producer that is planning on it being as dry this growing season as last year because if he was, he surely would just leave his seed in the bag and not plant it.

With that being said, since we are planning on a good year with adequate rainfall, which will lead to more disease pressure, we need a variety like AU-NPL 17 on some of our acreage to spread our risk around. When we get behind spraying our fungicides or delayed at digging time, this variety offers a little more leeway than with some of our other varieties.

Adjust Other Practices For Shortened Rotations

Georgia and the Southeast could see an increase in peanut acreage in 2024. This depends largely on the price of cotton and other crops as we move closer to planting time. An increase in acreage starts to erode away potential benefits of rotation as growers will likely need to shorten the interval between their peanut crops to remain profitable. This management choice can be successful as long as growers adjust their production practices to account for potential increases in pest pressure.

Planting date will also be an important factor. Increasing acreage will push growers in some areas to plant earlier. Planting early (in April) is not a poor decision. Growers should watch the weather and adjust their production practices to minimize stand issues and manage thrips to minimize Tomato Spotted Wilt Virus. Weather conditions play a big role in getting an adequate stand. University of Georgia Extension recommends planting after soil temperatures reach 68 degrees in the top 4 inches without a risk of a cold snap seven to 10 days after planting. This will ensure the peanut seed has every opportunity to germinate and emerge quickly and, hopefully, provide adequate stand counts of four plants per foot or better.

An adequate stand that emerges quickly along with using Thimet will prove helpful in reducing the risk of TSWV. Growers can determine their risks by using the Peanut Rx tool at https://peanutrx.org/. Even though UGA Extension stresses the importance of managing TSWV early, it can be (and has been) a problem throughout all planting dates. Stay vigilant when it comes to TSWV pressure and management. Contact your local county Extension agent for more information.

Be Ready For The Critical Weed Competition Period

Early season weed management is most important, which means weed control later in the season should be easier. There are roughly five critical herbicide application timings in peanut production. These application timings include preplant burndown (PP), preplant incorporated (PPI), preemergence (PRE), early postemergence (EPOST, 10-20 days after planting), and postemergence (POST, 30-45DAP) applications. A research study found that the critical periods for weed control in peanuts were from 4.3 to 9 weeks after planting for grass weed and 2.6 to 8 weeks after planting for broadleaf weeds. (Everman et al., 2018). Peanut yields decreased as weed interference intervals increased. Therefore, the use of PP, PPI and PRE herbicides are critically important for minimizing weed competition during the early season.

April is a good time for planning and applying PP and PPI herbicides in your peanut fields, while PRE herbicide applications are made at planting. Early emerging weeds, such as Russian-thistle and kochia, can be controlled by tillage or the use of burndown herbicides. One of the strengths of paraquat is Russian-thistle, and glyphosate is effective on a broad spectrum of annual and perennial grass and broadleaf weeds.

Preplant incorporated herbicides labeled for peanut include ethalfluralin, pendimethalin and trifluralin. These dinitroaniline herbicides, also known as yellow herbicides, are effective on annual grasses and small-seeded broadleaf weeds such as Palmer amaranth (carelessweed or pigweed), Russian thistle (tumble weed) and kochia (iron weed). They are ineffective at controlling large-seeded broadleaf weeds such as cocklebur, sunflowers and sedges (yellow and purple). Use of a PRE herbicide will enhance control of some of these weeds.

Please read the label carefully for recommendations regarding effective incorporation methods for these PPI herbicides. If the incorporation is too deep, and peanuts are planted shallow, peanut roots from planted seed have to go through treated soil, which can result in stunting.

Once Planted, Much Of The Crop’s Yield Potential Is Set

As we move closer to planting, it becomes important to put into place a set of key practices to establish the highest possible yield potential. From a pest management standpoint, we need to consider the pests we have good options for after planting versus those pests for which we have few, if any, options available once the crop is planted. Weeds are a prime example. In the V-C region, we have challenges with dogfennel and marestail in the peanut crop in both reduced- and conventional-tillage systems. The only herbicide we have in the crop is diclosulam, which only provides suppression. It’s critical that control is complete for these weeds before peanuts emerge.

In the absence of insecticide options, we need to stack things in place to minimize damage from southern corn rootworm. Unless you have the flexibility to leave off fields that are finer textured with relatively poor drainage, the most effective approach for this insect is to plant as early as possible. In the V-C region, that is very late April into the first week of May. Pods will be more advanced and difficult to puncture when rootworms are present in July if we plant early. Burrower bug has been a sporadic pest in North Carolina during the past two years. While there are no data that I am aware of to support this, I think planting early might provide a similar advantage against this insect like we see with southern corn rootworm.

If you do plant early, you need a solid plan for thrips suppression. We get significant yield losses in our region if thrips injure peanuts for a prolonged period of time, and we run the risk of greater injury from paraquat when plants have noticeable injury from thrips. This requires a two-shot program. Most folks are applying insecticide in the furrow at planting followed by a timely application of acephate. With that said, we have some areas where imidacloprid is struggling to adequately protect peanuts from thrips injury. When coupled with the presence of acephate resistance in thrips in North Carolina, we may be at risk with some of our insecticide choices for this insect. Try to think about what you need to do to suppress thrips to avoid yield loss given some of the potential limitations of insecticides.

Additionally, greater suppression of thrips often leads to less tomato spotted wilt. We do have good resistance to this virus in our Virginia-market types, but we can run into issues if our plant stands are low. Our intensity of TSWV is lower than in Southeastern states but we can run into significant incidence of disease. Plant enough seed to get five plants per foot of row. This minimizes risk for TSWV and thrips.

The seed we plant is treated with fungicide and that allows us to get adequate stands. There is no substitute for an effective seed treatment. On the front end of establishing a peanut stand, it pays to inoculate peanuts for nitrogen fixation. Based on long-term data in North Carolina, the financial return on inoculation through in-furrow application is about 40 to 1 in new ground and 4 to 1 in rotated ground.

Taking care of problematic weeds, establishing an adequate stand, protecting peanuts from thrips injury during the first month of the season, ensuring biological nitrogen fixation and stacking things in your favor for insects that might be an issue later in the season are important to do prior to or during planting. Finally, nematodes can certainly be an issue. Hopefully you have information on risk of injury in all of your fields. Fumigation, in-furrow nematicide application and in-furrow insecticide treatments (aldicarb) have various levels of effectiveness against this pest. But the decision to manage this pest with these options occurs no later than planting.

There is a lot here to digest, but once we plant, much of our yield potential is set. We can make up some ground if our early season decisions and inputs are marginally effective, but the process is much more difficult, and it is really challenging and expensive to make up all of the difference.