Monday, May 27, 2024

Peanut Pointers: May 2024

Know Your Seed’s Germination Percentage

emi kimura
EMI KIMURA
Texas A&M AgriLife Extension
State Extension Peanut Specialist

Planters are slowly starting to roll this week in West and Central Texas and the Rolling Plains. South Texas peanut planting will start in the next two to three weeks. By this time, producers know what market types and cultivars they will plant; however, there are a few things to consider when planting different market types in a field.

Spanish- and Valencia-market types are better suited for fields with limited irrigation capacity due to their shorter-season characteristics. Runner- and Virginia-market types take longer to develop into maturity; therefore, they require more irrigation water. In addition, these market types stay in the soil longer, resulting in a higher probability of getting disease infestation. Planting the runner- and Virginia-market types into fields with a limited disease history can reduce the risk of getting disease by soilborne pathogens.

Texas A&M peanut breeding plots

In a field with history of nematode infestation, it is a good idea to use nematode-resistant cultivars. NemaTAM II was released by the Texas A&M AgriLife Research peanut breeding program. It is a high-yielding, high-oleic, large-seeded, runner-type peanut cultivar with resistance to root-knot nematodes. In a statewide peanut variety trial, NemaTAM II ranked first in a location with nematode infestation.

Finally, it is always important to use high-quality seed and check for splits and immature kernels prior to planting. Adjust your planting population based on the percent germination. This information can be obtained on the bag of seeds or by calling the supplier. You can also obtain percent germination by placing 100 random seeds on a wet paper towel, preferably multiple sets of 100 seeds, rolling them up, and putting them in a zip lock bag for five to seven days. Unroll and count the number of germinated seeds to obtain the percent germination. If the total is 80%, divide your seeding rates by 0.8.

Gypsum Availability The Topic Of Coffee-Shop Talk

Scott Monfort
SCOTT MONFORT
University of Georgia
Extension Agronomist

I hope planting season goes relatively smoothly this year, but realistically, growers are likely to have a few weather-related issues before all the peanuts are planted and emerged. Follow the 10-day forecast closely to limit potential issues. This is critical for planting in early May. Cool, wet weather, along with seed quality problems, caused many acres to be replanted last year. Hopefully, seed quality will not be an issue, but given last year’s growing conditions, I am a little concerned about this year’s seed quality.

To help minimize seed issues, I encourage growers to take care of their seed like they would a newborn baby. Keep seed in stable environmental conditions until planted. Handle with care, and do not plant in subpar conditions.

The seeding rate in relation to cost per acre is another thing to consider. It costs an estimated $20 for every seed per foot/per acre that you put in the ground. For example, six seed per foot costs a grower roughly, depending on size, $120/acre. If you plant eight seeds per foot, it would be an additional $40/acre.

Gypsum availability has been a coffee-shop topic of late. It (gypsum) is the primary way to obtain calcium for your peanut crop. It is available; however, it will either take some effort to secure, or it could be a different gypsum type. For example, most growers typically use AgriCal (smokestack/synthetic) or USG 500. AgriCal is the gypsum type that appears to be less available this year. PCS Phosphogypsum is also available, although it is not as widely used.

Lime products are another option for obtaining calcium needs as long as your fields need a pH adjustment. Timely lime applications occur before or at planting to allow lime to break down and calcium to become available.

For growers who are unable to secure the above-mentioned gypsum types, calcium chloride and calcium thiosulfate are some liquid calcium products you can apply at high volumes, 10 to 30 gallons/acre, through the pivot or on the ground and watered in. Although these products will provide calcium, they are not as effective as gypsum in suppling calcium needs for peanut. Polysulfate and calcium nitrate have also been tested, but at the current manufacturer’s recommended rates, they do not provide enough calcium for peanut.

Lastly, growers need to know that foliar calcium products applied at low rates will not work and are not recommended. Like always, call your local county agricultural agent for help.

Be Sure To Kill, Not Just Cover, Weeds

DAVID JORDAN
North Carolina State
University
Extension Agronomist

When we get into May, we have already invested a lot in the peanut crop and set the stage for yield potential. Weed scientists talk a lot about the critical period of weed interference. For peanuts, that’s generally during the first six weeks of the season. To optimize yield, we need the crop to grow without competition from weeds during this time. Certainly, we need to dig peanuts, and weeds that come in later can interfere with that process and create major pod loss. However, controlling weeds during the first month or so after the crop emerges really sets the stage for optimizing yield. That is why we encourage an effective burndown program for reduced tillage and adequate, uniform tillage in conventional tillage.

Thrips injury on untreated peanuts.

The money we spend upfront brings in a dividend. If you can incorporate a herbicide, that is a great start. If not, apply residual herbicides right after the planter, and add a contact or systemic burndown to the mix if there are emerged weeds. This happens sometimes when we till and get delays in planting. We get out of sync. Another challenge can be wet weather prior to tillage. Sometimes we are just covering up weeds and not killing them when we disk. The result can be that in a few weeks, you have 12-inch weeds scattered across the field. If there is any doubt about how well you can kill all the weeds with tillage, apply an effective burndown before you begin tilling. It may seem like a waste, but if you are just covering up some of the weeds with a disk, you will be chasing them in a few weeks.

After planting, and regardless of how good you think your weed control is, make sure you don’t have any small escapes. I often recommend paraquat plus Basagran plus residuals about three weeks after peanuts emerge. In the Southeast, Storm plus paraquat is used a great deal. Either combination serves the purpose of cleaning up the weeds that slipped through at-planting herbicides.

In the Virginia-Carolina region, it’s critical to stay on top of thrips. We are often a week or so late for our foliar sprays to suppress this insect pest. If peanuts are stunted and terminals are in poor shape, we are indeed late spraying, and we may have experienced yield loss and greater transmission of Tomato Spotted Wilt Virus. Be proactive on these sprays.

As we move through May, we might have some fields that have less-than-ideal stands. What does less-than-ideal mean? In a perfect world, you would have four to five plants per foot of row all the way across the field. What if you have three plants or perhaps two? I would say three is OK, but yield will be lower than four or five. But, I wouldn’t replant if I had at least three across the field. Less than two needs replanting, while between two and three can be a gray area. Peanuts can take a long time to make a stand, especially in the upper V-C, and that can make it challenging to know whether to jump in with a replant or plant a few more seed to the side of the initial planting. Large gaps in stands can be the major issue, and if you have many of those, a replant is needed. This type of situation most often warrants a phone call and discussion. In June, I’ll hit on fertility issues for Virginia-market types and some thoughts on fungicide programs.

Don’t Give Palmer Amaranth A Head Start

Kris Balkcom
KRIS BALKCOM
Auburn University
Extension Specialist

As you read this issue, I feel that we will be in full swing planting peanuts this year, which is different than the past two planting seasons. So far during the month of April, even though we have had some cool nights, our daytime temperatures have been relatively warm. Therefore, when you look at our soil temperatures, they also have been higher overall for April this year compared to the past two years. This makes me think about being more cautious in regard to seedling disease.

Aspergillus crown rot, in particular, is more prominent when we have hot and dry weather. Writing this ahead of time, I certainly don’t know what weather we will be experiencing at the time but hopefully it won’t be hot and dry. I just want us to be cautious and prepared. Some of us have had 25 inches of rain from the first of the year up until mid-April. Therefore, our best defense is to have the best seed treatment on the seed in addition to a fungicide in the furrow.

Also, I am still getting questions about the use of preemergent herbicides behind the planter damaging peanut stands. As I mentioned earlier, this year seems different than last year’s planting season. We experienced 10 to 15 inches of rain right after planting last year and it didn’t reduce our plant stands. This was mainly because of the high-quality seed and well-drained soils. Therefore, don’t hesitate and give palmer amaranth the chance to get a head start.

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