Mark Abney, UGA Department of Entomology
As we move into June concerns about thrips diminish, and we need to begin to look out for other insect pests that can attack peanut. I received a couple texts/calls in recent days about small caterpillars feeding on foliage. Though we did not positively identify them, the caterpillars were most likely tobacco budworm. It has been several years since there was an early season tobacco budworm outbreak, but it can still happen. The fact that folks are noticing them suggests that we need to be paying close attention to fields in the coming weeks. It doesn’t take a lot of caterpillars to cause significant defoliation on small peanut plants, and it doesn’t take long to happen either. Walking fields once a week to check for insect infestations is the best way to prevent losses. Remember that caterpillar thresholds in peanut range from 4 to 8 larvae per row foot. We will want to use the lower end of that threshold on peanuts that have not lapped the row middles. In addition to tobacco budworm, it is not uncommon to find beet armyworm and cutworm larvae on peanut in June, though neither commonly require any treatment.
Despite recent rainfall, lesser cornstalk borer moths are being caught in pheromone traps in Georgia peanut fields. This does not necessarily mean that we need to treat fields, but it is a reminder that the insect is present, and hot, dry weather could result in damaging infestations. Again, scouting is the only way to know for certain if lesser cornstalk borer larvae are present at levels that warrant management.
Climate Outlook for June 2024
Pam Knox, Agricultural Climatologist
Welcome to summer! Climatologists designate the months of June, July, and August as the official climatological summer instead of using the astronomical dates. Here is your outlook for June 2024 and beyond.
Temperatures across the region have been running warmer than normal, and that is expected to continue over most of June and the rest of summer as global temperatures continue to rise. That does not mean every day will be scorching hot, but you can expect to see degree days accumulating a little quicker than in previous years for both crops and pests (vegetable and insect) that are affected by temperature. The ample moisture we have had over the past month will allow clouds to develop more often than usual, keeping solar radiation a bit lower and also reducing daytime high temperatures but increasing overnight temperatures. The coolest period will likely be early June, with warmer temperatures and higher humidity returning by the second week and lasting the rest of the month.
Rainfall in the Southeast has been generous to say the least, and many producers are behind in planting and other field work because of that. The current weather pattern continues to favor wet conditions for the next few months, so I don’t see a big switch to dry conditions any time soon, although that could change by fall once La Nina starts to develop. Fortunately, there will be some dry periods interspersed between showers that will allow fieldwork to take place, but be sure you watch your local forecast if you are applying anything that needs rain (or needs to avoid it). Spotty showers in summer are always hard to predict and your local conditions may vary depending on exactly where the storm cells go.
This is the start of the Atlantic tropical season, so if you have not done your preparations, now is a good time to do it. This is one of the slowest starts to the tropical season since about 2009, but don’t let that fool you. There is no correlation between when the first storm is named and the number that we get in a year, and as El Nino fades away and is replaced by La Nina, the tropics will become more active.
Favorable water temperatures are already present in the Atlantic and the Gulf of Mexico, but there is enough residual wind shear from El Nino to keep early tropical waves from developing. The long-range models indicate the second half of June will be much more favorable for tropical storms, so we are likely to see something by the end of June, but no telling where it will go if it does form.
Let me say a word about social media. One of the global models is already indicating the potential for a hurricane to hit Louisiana by mid-June. However, that model, the GFS, is known to whip up hurricanes at the drop of a hat and many of them disappear in the next model run. So be very careful of any forecasts you see on social media because they are likely to be a single (worst-case) model run that does not show a storm in the next run. But also keep in mind that even if it is not a named storm, it could provide windy conditions and a lot of rain, so it may have an impact on agriculture even if it does not have a name.
Your best source for information is the National Hurricane Center at https://www.nhc.noaa.gov/. They will watch all the models for consistency before predicting a storm will develop. I will also send out more information when a credible threat approaches.
Early to Mid-Season Irrigation for Peanuts
Phillip Edwards, David Hall, Daniel Lyon, Jason Mallard, and Wesley Porter
This year has brought excessive rainfall across most of the state. That is not to say that we may not be dry in other areas and needing irrigation. We have started to require irrigation on all of our corn treatments and on some of our peanut irrigation treatments. While the first week of June has not brought much rain, it’s forecasted to become rainy again in mid-June. While we always need rain, the high amount over the past month has made it difficult to finish planting. Another consideration is that peanuts may have been exposed to saturated conditions for the early part of the season hindering deep root growth and development. Thus, when it does start to dry out, we may require irrigation faster than normal as we will not be accessing deeper moisture in the profile. It is a good idea to check rooting depth and pull a few soil samples to check current moisture conditions and depth in the profile. Keep track of the graph below or use our Irrigation Reference Guide for Corn, Cotton, Peanuts, and Soybeans in the field throughout the month of June to stay on top of your irrigation requirements. Contact your local Extension office if you need a copy of the irrigation reference guide. If your peanuts were planted during late April or early May, most of these earlier planted peanuts are beginning to bloom, so expect water usage to gradually increase. Peanuts will begin flowering on average around 40 days after planting.
Remember the water requirement is IRRIGATION and RAINFALL! Also consider irrigation efficiency especially on hot dry days. A typical pivot is 85% efficient, so don’t under-irrigate, but at the same time don’t over-irrigate either as research has shown reductions in yield just as significant for over-irrigating as for under-irrigating. The problem with over-irrigation is that it brings a larger loss in profitability due to the additional cost of non-needed irrigation. Good record keeping and a sound irrigation scheduling strategy can aid significantly in increasing profitability in multiple ways, including reductions in irrigation applications, correlating to reductions in energy requirements, and potentially increases in yield.
A couple of quick reminders regarding irrigation of peanuts. Early irrigation applications can tell you very valuable information regarding your water application uniformity. If a Mobile Irrigation Lab test was not conducted, pay close attention to the way your soil dries out after an irrigation application. If your peanuts were planted into conventional tillage, this will be easy to see especially prior to full canopy closure. Visible bands drying out quickly or bands staying wet for longer periods are signs of poor uniformity. Go to these areas of your pivot and address them now. As the peanut canopy develops and laps, the obvious signs will not be visible. Hot dry weather makes it easy to see if your pivot was working properly due to the extreme heat and drought. The under applying nozzles are easy to see by the evidence presented as stressed crops in bands under the pivot. Doing the same thing twice expecting different results is never good.
Lastly, if you are using soil moisture sensors there are a few things to consider early on. Many times, sensors are “soaked in or wetted up” during installation and require a little time for moisture levels around the sensor to return to field conditions. Keep in mind that we begin to use the individual sensors on the probe as the roots reach the particular depths, therefore sensor readings should be weighted in making decisions early during the season. If you have “weighted” the sensors, be sure to adjust accordingly as the root systems develop. Consider using other tools in conjunction with your moisture sensors. Irrigator Pro (https://irrigatorpro.org/) integrated with a soil moisture sensor system through UGA trials has repeatedly shown higher yields than the Checkbook method. For more assistance and information on Irrigator Pro usage or any other irrigation scheduling tool for peanuts, contact your local UGA Extension ANR Agent.
Assessing Plant Status and Replanting
R. Scott Tubbs
With very wet conditions across most peanut fields, plants may experience abnormal early season growth. I have observed erratic emergence, with some plants larger than two fists growing within a few feet of other seedlings just cracking through the soil. In other cases, plants may be stunted and/or having a yellower-than-normal hue. It is not always easy to pinpoint the cause of these symptoms, as it could be related to a pathogen, insects, fertility, or deteriorated root structure. In the event of the latter, the plant’s root system may not be capable of taking up pesticides or fertilizers, meaning the symptomology may not be something that is recoverable by applying chemicals and/or fertilizers. In other cases, it may just be a matter of allowing the soil to dry and for the plant to begin growing normally. Checking below-ground is very critical to determining whether the plant may respond to chemical/fertilizer applications. If roots are rotting and incapable of uptake, then an application of a fungicide, fertilizer, etc. could be wasted money since the plant may have no mechanism for uptake. If the root system is healthy yet the plants appear yellow, this may be a result of insufficient N-fixation to meet the plant’s need while soils are saturated with water. Typically, this will correct itself without the need for N fertilizer application. Do not be hasty with a N fertilizer application on peanut to “green them up” since this can reduce nodule formation and end up slowing N-fixation later in the season when the plant’s N demand is at its maximum. When assessing the root system, check for adequate nodulation (there is no standardized level for what is considered “adequate”, but anecdotal information suggests around 20+ nodules per root is satisfactory), and be sure to check that nodules are considered active by slicing them open and assessing the interior color. Active nodules should appear pink to reddish-purple in color and give a slightly “wet” sheen to them. Inactive nodules will be brown or green and have a drier appearance on the interior.
With regard to replanting, this year has been atypical. When replanting is needed as a result of poor germination, the recommendation is to conduct a “supplemental” replant by dropping additional seed in an adjacent furrow parallel to the original row. However, when there are multiple large washouts in a field that will affect other equipment operation in the field throughout the growing season (such as fungicide applications), there are situations where smoothing the soil surface is necessary and complete replanting is needed (at least in certain sections of a field). However, when we get into June, plowing up the original stand and starting over is not a recommended practice. If washouts occur at this stage, running field conditioning implements should be minimized, only enough to repair the rut. Replanting should only be through supplemental means by maintaining the already emerged plants in their original furrow (where any previous pesticide applications will retain efficacy) and by supplementing the stand with a reduced seeding rate that is dependent on the original population. It is usually recommended to make a supplemental replanting within 21 days after the original planting, however this has not been possible in many areas this year. If replanting occurs more than 21 days apart, expectations will need to be tempered on the value that the replanted peanuts will provide. The replanted peanuts are already getting a late start, and the original peanuts that were previously established will be larger and competing with the new seedlings for space, water, light, nutrients, etc.
Maturity will also need to be closely monitored this fall with replanted peanuts. The leading edge of a peanut maturity profile board is misleading when there are replanted peanuts with two different maturities growing in the same field together. A field that was supplementally replanted should be left in the ground longer than the original plant stand’s maturity would suggest. Data suggest maximized
yield and grade occurs when you dig peanuts halfway between the maturity of the original plants and the replanted plants. Essentially, if replanting occurs 20 days after the initial planting, then you will need to add an extra 10 days to the suggested maturity from the maturity profile board to get the most benefit from the replanted peanuts. Naturally, this is dependent on having healthy vines and pegs on the original plants that will hold on without suffering major losses from defoliation and weakened pegs.
Variable Rainfall across South GA
R. Scott Tubbs
The cumulative rainfall for the month of May was fairly variable across South Georgia. From the UGA Weather Network (gerogiaweather.net), total rainfall was less in the eastern parts of Georgia’s peanut belt (Midville = 5.74”; Baxley = 4.73”) and substantial in western areas (Plains = 10.22”; Albany = 9.19”), with some of the more concentrated peanut production areas falling somewhere in between (Attapulgus = 7.03”; Tifton = 7.66”). Regardless, all areas received precipitation that was well above average. In both Tifton and Plains, these amounts are significant departures from the norm, with Tifton’s amount in May roughly the same as May from the last 4 years combined, and Plains receiving around the total of the last 3 years. Midville has a steadier range of planting season rainfall, with 6 of the last 8 years receiving at least 3” in May, and with a cumulative monthly total of between 2.4-5.7” in 6 of the last 8 years. By contrast, Tifton has received 3” or less in 6 of the last 8 years.
Although, cumulative totals don’t always tell the whole story. Tifton has had 12 days since May 1 with a “measurable” rainfall (at least 0.02”). However, 7 of these events measured at least 0.7” for the day, sometimes occurring on back-to-back days. During the 17-day span of May 3-May 19 (the prime peanut planting window), there were 9 rain events and never more than 4 days between rain, not allowing enough time for the soil to dry enough to get equipment back in the field in most areas. Just as things started to dry out, another 1.0” was received between May 25-27, setting things back a few more days.
The fortunate saving grace in all of this is that average PAR (light/radiation) received during the month of May has been suitable for crop progress, all things considered. Values were greater in all locations in 2024 than in 2023, despite having almost twice as many rainy days as last year. Therefore, the peanuts that emerged prior to the rains have progressed relatively normally if they were not drowning or suffering from rotting roots.
However, at the time of writing, the extended forecast shows a 50% or greater chance of rain in most of SW and South-Central Georgia for June 12-16. Hence, it is imperative that we not only get the majority of the peanut seed planted prior to this time, but also not forget about getting our first protective fungicide applications on the early planted crop before we get wet again and can’t put equipment in the field for another 5 to 7 day stretch.
2024 Peanut Pointers (Disease Update) – June
Bob Kemerait
There comes a time….. disease time.
“Comes a time when your driftin’, comes a time when you settle down….. There comes a time, there comes a time….” These lyrics, from one of my favorite Neil Young songs (yeah, I know, a southern man don’t need him around anyhow…), make me think of a peanut crop as it enters the month of June. For optimal disease control in any peanut, corn, cotton, or soybean crop, a grower MUST initiate a fungicide program early enough that disease is not yet established in the field. This is especially true for a peanut crop that can be crippled by early leaf spot, late leaf spot, southern stem blight (white mold), or Rhizoctonia limb rot if any of these are left “unchecked”. Almost all peanut growers in the state, unless planting is delayed, should be spraying their peanut crop with fungicides in June.
Many growers begin to spray their peanuts for leaf spot as early as 30 days after planting. We have many options with which to start a leaf spot program. These range from chlorothalonil alone to tank- mixing with products like Alto (cyproconazole) or Domark (tetraconazole). Pre-mix products to include Aproach Prima (picoxystrobin + cyproconazole)and Absolute Maxx (trifloxystrobin + tebuconazole) are also available for the 30-dayish application. Where Velum was used in-furrow, the 30-day application for these products can be delayed until approximately 40-45 days after planting.
I am often asked if something should be included in early fungicide applications for management of white mold. Growers who apply Priaxor (pyraclostrobin + fluxapyroxad) or Lucento (flutriafol + bixafen) at 45 days after planting will get excellent leaf spot control and a bit of white mold control. Growers applying chlorothalonil could mix in tebuconazole (even at 30 days if they like) to add some measure of white mold control. It is not absolutely necessary at that early timing, but it could provide insurance, especially in fields with short rotation and favorable weather. (Our most important timing in which to fight white mold remains between 60 and 104 days after planting.)
There are several important reasons why June is “white mold time”. First, temperatures are warming considerably as we enter the summer season. As you know, outbreaks of white mold are fueled by warmer soil temperatures (and by warm nights). Second, there is often increased chance for rainfall as we move into June. Warm soil temperatures and moist conditions are critical ingredients for the development and spread of white mold. Third, our peanut crop is now growing to a point where a canopy of leaves is present. Higher humidity and periods of leaf-wetness will increase within the canopy as it continues to expand during the season. This warm, moist environment is essential for outbreaks of white mold.
The “backbone” of white mold management remains the use of appropriate fungicides over the period between 60 and 104 days after planting. This is our historical “white mold management block”.
However, there has been a revolution in the management of white mold since I started in 2000. Not only do we have an expanding arsenal of effective fungicides for the management of white mold, but the cost of fungicide tebuconazole has dropped allowing creative new programs. Based largely on the research from Dr. Tim Brenneman’s program, we also manage white mold more aggressively than we may have done years ago. The most obvious changes have been 1) the expanding arsenal of excellent products, 2) the value of applications of fungicides at nights, 3) the value of banded applications of
Proline and Abound within five weeks of planting, and 4) the value of early-season broadcast applications of tebuconazole.
As a refresher, here are our current recommendations for the management of white mold.
- All growers should use deploy some fungicide program for the management of white mold over the period of 60 to 104 days after planting. The specifics of that program is influenced by the severity of the risk to white mold (see Peanut Rx) and the fungicides that are included in the fungicide program.
- All growers should consider the opportunity to tank-mix tebuconazole (7.2 fl oz/A) with chlorothalonil early in the season. Such a tank-mix is affordable and provides a start to leaf spot and white mold control
- Applying fungicides for the management of white mold at night or in the very early morning while leaves are still folded remains an effective tactic to optimal placement of the fungicide in the crown of the plant. Some thought should be given to maintaining optimum control of leaf spot since only the underside of the leaf will be treated at night; however this is easily addressed with the use of a systemic fungicide.
Starting a peanut fungicide program on time with the right combination of fungicides can make a tremendous difference in the success of the program. There comes a time….