Peanut Pointers: May 2023

After Making A Stand, Assess Gypsum Needs

Planting season is underway! Two of the most important points to remember, as seed are going into the ground, are germination and seed storage. First, ask for the percent germination of each lot of seed you purchase, and record it with your planting data. Second, take care of your seed and protect it from extreme temperatures and moisture by placing it in proper storage until planting. 

In May, soil temperatures at planting should not be a concern; however, do monitor soil moisture. As you are planting, if soil moisture starts to disappear and temperatures are hotter than normal, hold up! Do not chase moisture in dryland fields as it might dissipate before the seed can imbibe enough water to germinate. For irrigated fields in the same situation, growers need to make sure to irrigate before and after planting to ensure the seed has the best opportunity to germinate and emerge. 

Growers should assess fields at or before 14 days after planting to make sure they have an adequate stand. If a replant decision needs to be made, the quicker the better. Do not use fertilizers or unproven products in-furrow with peanut seed as it may affect your stand.

Once an adequate peanut stand is obtained, growers need to make decisions on their calcium needs. A pegging-zone sample is the best way to determine if a field is sufficient in calcium. University of Georgia Extension recommend at least 500 pounds per acre of calcium and a calcium-to-potassium ratio of at least 3:1 in the pegging zone. If either of these levels are not met, then apply 1,000 pounds per acre of gypsum at early bloom to runner-type peanuts. Furthermore, if you are growing peanuts for seed, growers need to apply 1,000 pounds per acre of gypsum at early bloom, even if these levels are met. 

Remember, the Extension service in each state is here to help. Please call your county Extension office if you have questions or comments. 

Watch For Thrips Injury And Treat Accordingly

As we move into May, we hope to have weeds under control and thrips suppressed well enough to prevent yield loss and minimize Tomato Spotted Wilt Virus. In some cases, we may need to make decisions about replanting. Each year, there may be issues with seed quality or with poor conditions for germination and emergence of peanuts. 

In the upper Virginia-Carolina region, I have seen it take three weeks for peanuts to make a stand. Two weeks is not uncommon. As we move into late May and June, it may take five to seven days to make a stand. 

Several researchers have looked at what population warrants either a complete replant or planting beside what you already have. My rule of thumb is that if you have less than three plants per foot of row, you need to plant more peanuts. Rather than destroying what you have, I would encourage you to plant off to the side and leave the plants you have. I would not plant less than four seeds per foot. 

You will need to include a systemic insecticide when you replant and the inoculant for nitrogen fixation as well. The seedlings need to absorb adequate levels of insecticide to control thrips and the root system; in particular, the taproot needs to be infected by bacteria for nodule formation and nitrogen fixation. 

For growers who use AgLogic or Velum (for nematodes along with imidacloprid or phorate for thrips), this can be a hard one to swallow. If you used an expensive program for the first planting, you might shift to the less-expensive program for the second planting. You cannot rely on the root system of the second planting to reach the insecticide and inoculant included with the first planting. 

The reason I stick with at least four seed per foot is because there will be gaps even though the average across the field may be closer to two seed per foot. The four seed per foot replant gets you close to four plants per foot across the entire field if seed quality is good.

We are often looking at ways to cover risk by spreading out harvest. In the V-C region, especially North Carolina and Virginia, we gain little with respect to harvest when we spread out planting. A three-week difference in planting often equates to a one-week difference in maturity in the fall. Peanuts planted late often catch up with earlier-planted peanuts. 

Several years ago in a planting date trial, peanuts planted May 5 emerged the same time as peanuts planted May 15. Of course, if I had many acres, it might be helpful for those peanuts to be planted early if I had good assurance they would emerge okay. This is where good seed quality and an effective seed treatment are critical. Our most popular Virginia-market type varieties (Bailey II, Emery, Sullivan) reach optimum maturity at about the same time when planted on the same day. There is just not much room for spreading out harvest with our varieties and planting dates.

As you move through May, keep your eyes on thrips injury and treat accordingly. Make sure injury from thrips is not excessive if you are applying paraquat plus Basagran or Storm plus paraquat. Take care of the thrips first, and give the peanuts time to recover before applying contact herbicides.

Planting Into Cool Soils Is A Risk To The Seed

We have received a limited amount of winter precipitation in the Southwest. West Texas, Texas Rolling Plains, South Texas and Central Texas received 0.5, 1.6, 3 and 7 inches of precipitation from January to March, respectively. We need more rain in April to ensure successful peanut stand establishment. 

In addition to adequate soil moisture, soil temperature is an important factor for seed germination. The optimum soil temperature for peanut germination is at least 68 degrees Fahrenheit for three consecutive days without a cold front in forecast. 

Weather during the planting window in West Texas, the Rolling Plains and Oklahoma are often unstable and fluctuate between below 50 degrees to above 80 degrees. If seeds are planted into cold soil, they may stay in the soil for long periods without germination, which can increase the chance of disease and pest infestation.

Early season weed management is very important. There are eight herbicide-resistant weed species in Texas that are officially recorded in the International Herbicide-Resistant Weed Database. Those weeds are:

→ Common sunflower, Palmer amaranth and tall waterhemp – resistant to glyphosate
→ Johnsongrass – resistant to imazethapyr and nicosulfuron
→ Kochia – resistant to metsulfuron-methyl
→ Palmer amaranth – resistant to Atrazine
→ Barnyardgrass – resistant to Propanil
→ Perennial ryegrass – resistant Sulfometuron-methyl

There may be other species that are resistant to herbicides not listed above in your specific fields. Please check fields following a herbicide application and record any weeds that are not controlled by the herbicides. Collect these as samples. Talk to your county agent about the potential for herbicide-resistant weed species in your field. 

Look For A Pattern In Stand Gaps To Determine A Cause

May is a busy month for the farmer mainly because it is prime planting time for peanuts, although some of the crop may be planted in April. Besides trying to maneuver around the farm and get all the peanuts planted, you are also trying to assess what has been planted to determine if you have an adequate stand everywhere. 

Timeliness is everything to backtrack on crop plantings and assess the stand because if any fields need re-seeding, we need to be aggressive and replant in a timely fashion. 

First, try to determine what caused the problem. There are several factors that can prevent a good stand of peanuts, such as: percent germination, soil temperatures, soil moisture, seed-to-soil contact, seedling disease and herbicide damage. 

Next, what type of stand do I have? Is it a uniform solid stand, skippy and erratic across the field, or maybe just a planter unit problem consistent across the field? Does the plant stand have huge gaps in it or small amounts of variability between the emerged plants? Look for a pattern of some kind, whether it is soil type, moisture from a terrace channel, a bottom or sandy flat, or maybe two different seed sources or varieties. One of these factors should indicate a possible problem. 

We know we want to have a final plant stand of four plants per foot for maximum yield. However, if Tomato Spotted Wilt Virus isn’t an issue, we can achieve respectable yields with as low as 2.5 plants per foot. Hopefully no one will be in this situation this planting season, but if you are, make some stand counts and determine what caused the problem, then decide to replant or not. PG