Hopefully everyone has finished up planting or is almost done by now. I know we have had some seed quality issues with the crop in some places this season, but maybe yours is off to a good start. If not, remember, we recommend 6 seed per foot of good seed to have a final stand of 4 plants per foot.
The research over the years has shown us that we can still make respectable yields, with only 3 plants per foot. Now, that’s not what we want, but it is still achievable if we have good growing conditions.
If you go to the field and take several stand counts scattered all over the field and are under the 3 plants per foot, you may want to patch in some more seed. I would make sure I went ahead and replanted as soon as possible to reduce the time difference between crops.
Also, go ahead and spray for weeds if you need to keep the weed pressure down. Plus, the herbicide will help slow down the progress of the first crop of peanuts planted.
If you have a great stand, start with the normal herbicide maintenance for weeds and preparing to get started with your fungicide program, especially if you are around that period of 35 to 45 days after planting.
Right after you finish planting is also an ideal time to check back over those soil samples. Or, you may need to pull some pegging-zone samples to make sure you have not missed a low calcium level. You can do everything right, but a lack of calcium will hurt yields. Make an extra effort to double check this needed nutrient.[divider]
Apply Gypsum Before Bloom Stage
Growers are on the tail end of planting in Georgia with the earliest planted crop closing in on 25 to 35 days old. It is truly a busy time for growers trying to finish planting both peanuts and cotton along with trying to manage weeds, irrigation and initiate fungicide programs.
In the middle of this craziness, growers also need to keep in mind the calcium needs of the crop.
As a grower, you should have a good idea of your calcium levels in the field from your soil samples pulled in the spring. You can also take a “pegging zone” sample to determine if there is adequate calcium for pod development, increased yield and improved grades.
The pegging-zone sample is taken just like a regular soil sample for fertility except for the depth of the sample (3 inches for the pegging sample).
Since the gypsum needs to be applied before blooming stage initiates, the pegging-zone sample needs to be taken as soon after emergence as possible. The current UGA recommendations for calcium for peanut are 500 pounds per acre of calcium in the pegging zone and at least 3:1 ratio of calcium to potassium.
For fields that do not meet both of these recommendations, an application of a 1,000 pounds per acre of gypsum for runner-type peanuts and 2,000 pounds per acre for Virginia-type peanuts is recommended at early bloom. Application of 1,000 pounds per acre of gypsum is recommended automatically for seed producers.
One thing growers need to remember about calcium is the peanut plant cannot translocate calcium in the plant from the leaves down to the pod. Peanut pods absorbed calcium directly from the soil solution surrounding the pods. Therefore, an application of a foliar-applied calcium does not work.
With this in mind, growers need to be cautious of calcium products being marketed as an alternative to gypsum, especially where you are recommended to apply small amounts.
On the other hand, there are a few liquid calcium products available, but you have to apply 10 to 30 gallons per acre and irrigate in after application to meet the calcium needs in peanut. These products only work where you have irrigation and can water them into the soil.
The bottom line is know your situation and make the best decision you can. Need help? Enlist help from your county Extension agent, consultant and/or Extension specialists in your area. You can also go to the following website to download the latest recommendations from the UGA Peanut team at http://bit.ly/uga-eguide.[divider]
Stay Committed Season-Long
It’s June. How would you rate your weed management? Use of preplant herbicides, whether burndown, incorporated or both, was a great first step to start clean. At-plant and early postemergence (EPOST) residual herbicides or both, were a great second step. Unfortunately, these soil residual herbicides may now be starting to break and new weed flushes are emerging.
There are a variety of postemergence herbicide options in peanut that will control emerged weeds.
All herbicides have strengths and weaknesses. Weed Science Society of America (WSSA) Group 14 herbicides, such as Cobra and Ultra Blazer, are contact-based herbicides that require thorough coverage. They are effective on weeds less than 4 inches in height.
WSSA Group 2 herbicides, such as Cadre and Pursuit, are effective on a number of annual broadleaf and grassy weeds and nutsedge. They have an 18-month cotton rotation restriction.
The use of 2,4-DB (Butyrac or Butoxone), a WSSA Group 4 herbicide, also can be an effective option to control emerged weeds. According to the Butyrac 200 label, applications can be made to control annual morningglories, cocklebur and other broadleaf weeds from 2 to 12 weeks after planting.
Best results will be obtained when weeds are small and actively growing. It is often used in combination with other herbicides, such as with Gramoxone after ground-crack (GC) to 28 days after GC or EPOST with Cobra or Ultra Blazer. A second application may be needed for late-emerging weeds or following suppressed control of weeds like prickly sida.
When weeds have exceeded optimum size for control by other herbicides, 2,4-DB can be a good tankmix partner. The second application should be made no later than the late bloom stage. Avoid drifting on adjacent crops such as cotton because severe injury may occur.
Tank contamination is a major concern where application equipment is shared for use in peanut and cotton production. There are state-specific restrictions regarding rates and application cut-off dates after planting and before harvest.
Do not apply when peanut plants are stressed as injury may occur. Some phenoxy-type symptomology is likely even under non-stress conditions, which is often enhanced if a surfactant is used. Do not feed treated peanut vines or hay to livestock.[divider]
Be Timely, Increase Spray Volume
In June, effective weed management continues to be an important element of successful peanut production. Depending on planting and emergence dates, paraquat (various formulations) may not be an option. Applications must be made within 28 days after peanuts emerge.
Applying paraquat, along with Basagran and residual herbicides, is more effective when applied two to three weeks after peanut emergence.
It is important to be as timely as possible with PPO-inhibiting herbicides — Cobra, Ultra Blazer, and Storm — for several reasons. First, they are more effective when applied to smaller weeds, which are less than 3 inches tall. Secondly, when we apply these herbicides to larger weeds, we often get incomplete control and that pushes us to resistance more quickly.
We also need to optimize performance not only by being timely but also by applying higher spray volumes, for instance 20 gallons per acre provides better coverage than 15, and 15 gallons per acre provides better coverage than 10.
Coverage is important with contact herbicides like the PPO inhibitors. Reducing groundspeed is also helpful regardless of carrier volume.
By late June, it is important to have developed a solid fungicide program for leaf spot and stem rot. Some of the fungicides we are using have slipped in their performance compared with control they provided for leaf spot in previous years.
Rotating chemistry (sites of action), being timely and achieving adequate coverage are important as we move into some unknowns relative to leaf spot control. The pathologists in all states in the peanut belt have excellent information on how to approach developing effective fungicide programs.
The general recommendation for Virginia market types is to apply gypsum at or shortly before peak flowering. This is often in late June and into July, although a significant amount of gypsum goes out in early June.
In terms of thrips, populations are often lower and injury from feeding is less when peanuts are planted in early May than in late May or June.
However, if thrips numbers are high and injury is significant, an application of acephate is warranted. There is some debate about the impact of thrips injury on yield and some are questioning the performance of acephate. As with leaf spot programs, consult local experts to know how to approach thrips in June.
The further north one goes in the peanut belt the more important it is to make sure thrips populations are suppressed because of the truncated growing season in northern areas.
As you move later into June it is important to use caution when applying any insecticide as they can increase spider mites. Hot and dry conditions and overuse of fungicides and insecticides can create conditions that escalate this pest. This is especially true for rootworms, and growers are advised to look closely at the southern corn rootworm index when deciding on use of chlorpyrifos.
Late June is also a good time to consider boron and manganese applications. Manganese deficiencies are obvious in most cases while boron deficiencies are observed in pods at harvest. Most folks are applying these micronutrients across the board.
Make sure you consider the actual amount of elemental boron and manganese when you select products. While some products are easier to handle and mix, they may not supply what is needed to correct a deficiency.
June is a good time to look closely at nodulation, especially in new ground fields. If there is an issue with biological nitrogen fixation, the sooner it is addressed with nitrogen fertilizer the better.
In June and July there will be a lot of questions about mixing products. Regardless of what you decide to do with mixes, it is important to avoid mixes that settle out and create problems with spray equipment. We also need to avoid excessive injury and marginal pest control.