Sunday, July 25, 2021

Peanut Pointers

Check For Active Nodulation

• By Emi Kimura, Texas A&M AgriLife Extension, State Extension Peanut Specialist •

Peanut planting in the Southwest was delayed because of above-average rains we received in May. In typical years, we recommended checking the crop for nodulation development on the roots in early- to mid-June. This year, it is not too late to check for nodulation in July to assess the potential need for midseason nitrogen applications if nodulation is not found in adequate numbers. Close up picture of peanut nodules

Take random samples from multiple locations in the fields. Carefully dig plants and count the number of active nodules. When cut open, active and healthy nodules should appear reddish-pink inside because of the reaction of leghemoglobin. If the nodules are not reddish-pink on the inside, they are not fixing atmospheric nitrogen.

Supplemental nitrogen is not required if an average of 20 active nodules per plants is observed. If supplemental nitrogen is required, 10 to 20 pounds per acre of nitrogen should be sufficient, depending on the number of active nodules per plant and residual nitrogen in the soil and irrigation water. Excess nitrogen can increase disease problems. peanut field with yellow rows

The field photo below shows an inoculant application malfunction on row seven of an eight-row planter that led to little or no inoculant being applied. Yellow peanuts show nitrogen deficiency. An August nodule count on this Hockley County, Texas, runner peanut field was nine nodules per plant in the yellow rows and 73 nodules per plant on green rows.


Questions About Plant Growth Regulators

• By Kris Balkcom, Auburn University Extension Specialist •

We certainly have a late crop in general this year in Alabama since a large percentage was planted after mid-May. This has had many producers asking about what, if anything, could be done to speed up the crop.

I wouldn’t panic too much. We never know what kind of fall we will have. However, we have experience with late-planted peanuts before. With good rainfall and warm temperatures, we have made around 5,000 plus pounds per acre, which is a respectable yield.

Producers have also asked about using plant growth regulators in peanuts like they’re used in cotton. We know that with late-planted cotton, it pays to be aggressive with our PGRs to force the plant to be reproductive. However, with peanuts, we have not been able to have a consistent program for PGRs. Since a majority of Alabama peanuts are dryland and relying on Mother Nature for rainfall, this puts us in a vulnerable position. Essentially, it subjects us to the possibility of decreasing yield potential if we don’t receive the needed weather conditions after the PGR application. Therefore, I wouldn’t worry about trying to use a PGR material in peanuts right now. Concentrate on keeping diseases at bay, which will give us more flexibility at harvest time.


Some Parallels Between Kids And Peanuts

• By Scott Monfort, University of Georgia Extension Agronomist •

July is the midpoint for a majority of the peanut crop in Georgia. This brings about the parental instinct factor where growers want to provide everything possibly needed by their crop. As with my kids, I want to make sure that they are eating healthy foods to fuel their bodies. gypsum application in peanut

To keep your crop healthy and fed right, growers need to make sure to apply calcium — gypsum at 750 to 1,000 pounds per acre prior to blooming — and boron — 0.25 pounds per acre twice at 30 and 45 days after planting — along with other nutrients as needed. Applying the wrong type of product or rate will not offer productive results. Sort of like your kids getting only sugar instead of nutritious foods.

Another issue I wrestle with in regard to my kids is how do I ensure that they are getting what they need and are on the right track for growing at a healthy rate. At my kids’ annual wellness checks, we learn about their growth percentages, tips for healthy diets, what’s to be expected in the next year and the possible trouble spots.

Regular “health screening” of a crop will help you stay on target with your crop’s needs in a timely manner. Monitor the crop closely by using crop scouts or consultants. Ask a lot of questions of your county agent/specialist about proven products as well as the newer products to make sure you spend your money wisely.

Base your decisions on what makes economic sense for your operation. I have seen on too many occasions where growers are willing to cut back on the more expensive fungicides to pinch pennies. This rarely works. You wouldn’t cut corners for your kids. Your crop is your investment and good choices mean good business. In the long run, those decisions will bring rewards.

Finally, one thing I have learned as a parent and an Extension specialist is that bad things can happen even when you do everything right. Be willing to call someone for help like your local county Extension agent.


Gaining Flexibility At Digging

• By David Jordan, North Carolina State University Extension Agronomist •

Palmer amaranth in peanut
Palmer amaranth in peanut

Weed issues have hopefully been taken care of by the time we move into July. Of course, there will be some weed escapes, and growers are encouraged to be on the lookout for weeds that are generally controlled but have broken through control programs.

Of particular concern are Palmer amaranth and common ragweed, which have escaped intensive programs that include PPO-inhibiting herbicides (Cobra, Ultra Blazer, Storm, Valor). These escapes could be the first survivors of selection for resistance to this mode of action.

Caterpillars and worms can be an issue in July as well. The presence of corn earworms with resistance to pyrethroid insecticides and tobacco budworms that pyrethroid insecticides do not control very well move us toward the more effective yet more expensive products on the market. To get complete control of these, you will need to spend the money.
Although at the time of this writing spider mites have declined, by July things could change. It is important to make sure your insect control practices do not induce spider mite outbreaks.

Next on the list is implementing a solid fungicide program to control leaf spot and southern stem rot diseases. We have numerous fungicide options, and it is important to look closely at effectiveness, cost and presence of resistance in your area. Starting with a chlorothalonil treatment, often mixed with Alto, and then following up with two or three sprays for stem rot and leaf spot control is an effective program in general. The last few sprays need to contain chlorothalonil for late-season protection from leaf spot and resistance management.

Weather-based advisories are available in North Carolina to help fine-tune implementation of your fungicide program. One of our newest programs is Miravis plus either Elatus or Convoy. The latter two fungicides are for stem rot primarily, although Elatus provides leaf spot control as well. When the higher rates of stem rot materials are used, this fungicide program can provide an entire month of control of both diseases. This is appealing from a logistical standpoint. While expensive, this program is competitive given the length of control it provides relative to other materials.

This column could go on and on, especially if written by a plant pathologist, but in brief we have a lot of good options for leaf spot and stem rot control. Keys to success are timeliness of sprays and ensuring peanuts are protected from the R3 development stage through the end of the season. In the Virginia-Carolina region, the end of the season in which leaf spot is still active could be mid-September or it could run well into October. We have seen both scenarios.

Protecting vines all the way to digging is critical as this gives us the greatest flexibility in when we dig relative to pod maturity. We can let peanuts reach optimum maturity if vines are healthy and not diseased. We also know that a little bit of disease can increase rapidly and tie our hands and give us less flexibility when it comes to digging. Good leaf spot control starts in late June and July.

As we move through July into August, there will be questions about tankmixing pesticides, micronutrients and the plant growth regulators Apogee/Kudos. Most of our work shows that performance of these products in the mixture is maintained at an adequate level, but there are some exceptions. Make sure components of the spray solution stay in place and do not settle before mixing the tank. Keep agitation going, and don’t let a tank containing multiple products sit overnight. Your local Extension agent and Extension specialist as well as those in agribusiness who are around these mixtures all the time will have information on compatibility of many of the possible combinations that can be applied.

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