There are several key issues to address in May. The first is establishing an adequate stand of five plants per foot of row and then protecting those plants from stresses early in the season. Peanuts are resilient and can survive even under difficult conditions.
As long as peanut seed has good germination and is treated with a fungicide, we generally get an adequate stand. We can plant peanuts deep, down to the moisture, and that takes a lot of pressure off of the decision to plant or not when soil moisture is limited.
Keeping plants free from thrips feeding and from weed interference during the first month of the season are high priorities.
Expect to have both. Our preplant, PPL or PPI, and preemergence herbicides are critical in protecting peanuts from weed interference during that time weed scientists refer to as the “critical weed-free period.” Herbicides applied prior to and immediately after planting do not control weeds completely for the entire season, but they do allow peanuts to emerge and grow without competition for a period of time.
To get us through the month of May and then into June, we often apply postemergence herbicides, regardless of the earlier program. Paraquat applied two to three weeks after peanuts emerge can be very effective. This is a good time to shore up the residual control by including one of the products that fits this window.
At the same time, we need to make sure thrips do not cause too much damage. Our in-furrow, systemic insecticides provide a degree of protection, especially if logistical challenges are in play or products do not perform well. In many cases, a timely application of acephate can give added protection. Our research shows that the combination of paraquat, Basagran, residual herbicides and acephate works well and helps us move the crop through the first four to six weeks without stress from these two pests.
Being timely is the key. Sometimes our PPI and preemergence herbicides give only a short period of control, while other times that control can be surprisingly long. The same is true for thrips suppression. Some years our products don’t need a follow up, whereas in other years an early spray of insecticide is needed. Weather plays a major role in the effectiveness of these materials.
More recently, we have also started being more concerned about evolved resistance in many of our pest populations. With that in mind, scout early to help ensure your yield potential by making timely postemergence herbicide and insecticide sprays.
Minimize Weed Competition
We have received good moisture in March and April, which means that weed pressure may be high in the early season. Best management practices for peanut production include effective season-long weed management. Four weed management principles in peanut production are: 1. Start clean; 2. Use residual herbicides; 3. Be timely with postemergence applications; and 4. Know your weeds.
Early season weed management is most important and should mean that weed control later in the season is easier. There are roughly five critical herbicide application timings in peanut production. These application timings include preplant burndown, preplant incorporated, preemergence, early postemergence and postemergence applications.
Yield losses are minimized when peanuts are free of weed competition for the first four to six weeks after planting. The use of PP, PPI and PRE herbicides are critically important for minimizing weed competition during the early season.
Early emerging weeds, such as Russian thistle and kochia, can be controlled by tillage or the use of burndown herbicides. PPI 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. 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.
The use of a PRE herbicide can be effective at controlling annual broadleaf and sedge weeds. Preemergence herbicides must be applied and activated before weed emergence and some must be applied prior to peanut emergence to avoid crop injury. It is important to read the label carefully, especially for application rates based on your soil type, feeding restrictions, rain-free periods, rotation restrictions, herbicide groups and other issues.
Scout Your Stand Early
Do I have an adequate stand of peanuts? This is one of the worst things that we come across this time of year. When we find ourselves asking, “Do we have a good enough stand?” I hope that there aren’t many of you in this situation this spring, but I know we had a lot of quality issues with last year’s crop and some of that has spilled over into the seed supply.
It’s important to determine if there is an adequate stand early so there is time to replant if needed. First, determine what caused the problem. There are several factors that can prevent a good stand of peanut, such as percent germination, soil temperature, soil moisture, seed-to-soil contact, seedling disease and herbicide damage.
Next, determine what type of plant stand you have. Is it a uniform, solid stand or skippy and erratic across the field? Maybe it was a planter problem recurring across the field. Does the plant stand have huge gaps or small amounts of variability between emerged plants?
Look for a pattern of some kind. It could be soil type, a terrace channel, bottom or sandy flat, or maybe you had two different seed sources or varieties. You should be able to figure out if one of these was a contributing factor.
Plant six seed per foot to achieve a plant stand of four plants per foot of row for maximum yield potential. Take a simple stand count in various places across the field to determine the average plant stand. I typically like to see at least three plants per foot; however, under ideal weather, I have made stand counts averaging as low as 2.5 plants per foot that still averaged 4,500 to 5,000 pounds per acre dryland.
However, Austin Hagan, Auburn University plant pathologist, had a test over a four-year period that only showed one year out of four in which four seed per foot was statistically higher than two seed per foot in an irrigated scenario. The dryland test was more consistent with an increase in yield for the increase in seed per foot.
Therefore, irrigation or years with increased rainfall provided enough water for the plants to compensate and overcome skippy stands, whereas the dryland peanuts were more vulnerable to not having enough moisture to properly grow and produce enough pods to overcome the skips.
If you find yourself questioning your stand this year, make some stand counts and attempt to determine what the problem was. This may help you in deciding whether to replant or not.
A Proactive Planting Strategy
As I write this April 1, I can only hope that we are busy planting. April has brought some early warm conditions and a few rain showers. If the heat and rain continue, we should be in good shape to get the crop planted and provide seed with the best conditions to germinate and emerge. However, be prepared with a good offense if we are hit by a lack of rain with these high temperatures.
Do not chase moisture this year. Remember, seed quality is likely to be lower than in previous years. The more stress that is put on the seed, the more problems there will be in the crop. Taking a proactive approach when it comes to reducing stress on the seed and encouraging good emergence will aid in providing the best situation for peanut plants to thrive.
Be sure to add these important tips to your 2020 proactive planting strategy:
• Make sure pH and fertility issues are fixed.
• Start clean and remain clean by applying the right herbicide at the right time.
• Clean and calibrate all application equipment.
• Add additional in-furrow fungicides as needed to support the seed treatments.
• Irrigate before and after planting, if needed.
• Add an inoculant to ensure proper inoculation.
• Use Thimet to reduce the risk for tomato spotted wilt virus and to control thrips.
• Slow planting speed to ensure proper seeding rate.
• Do not apply any fertilizer products in-furrow at planting for any reason.
Finally, get out in the field. Revisit fields seven to 10 days after planting to determine if you have any stand issues that will need to be addressed. The Extension service is here to help. Please call your county Extension office for further assistance.