Worth Ag Update for April 28, 2023

Thrips and TSWV Management Reminders for 2023 – Dr. Mark Abney, UGA Peanut Entomologist

Peanut planting time has arrived in Georgia, and that means thrips season is here as well. Many of the decisions a peanut grower makes at planting will affect the risk of thrips infestation and the risk of Tomato spotted wilt disease. By now, growers should have a plan for managing thrips and TSWV, but here are a few reminders that you might find useful.

1. Use Peanut Rx to assess risk to thrips and TSWV. https://peanuts.caes.uga.edu/extension/peanut-rx.html The TSWV risk factors found in Peanut Rx are REAL. The validity of the risk index has been tested and proven again and again for more than two decades. If a grower is looking for a way to reduce the risk of TSWV infection, he or she should look no further than Peanut Rx. If it is not on Peanut Rx, it probably does not matter.
2. Every peanut field in Georgia will have thrips, and thrips feeding reduces yield. Thrips management is a wise investment.
3. Killing thrips is a good thing to do, and there are several insecticide options from which to choose. But as odd as it may seem, killing thrips does not reduce the risk of TSWV. The only chemical known to reduce the risk of TSWV in peanut is phorate (Thimet). If you have questions about why this is true, contact your local UGA county Extension agent.
4. When the seed furrow is closed, opportunities for TSWV management are over. We can make foliar insecticide applications to manage thrips, but these sprays will NOT reduce the risk of TSWV.

Tomato spotted wilt disease was common in Georgia peanuts in 2022, and there is a lot of concern about the disease going into the 2023 season. While no one can predict year to year variations in virus abundance, the factors that affect risk are well known and have not changed over the last two decades. We planted a lot of the 2022 crop in a high risk environment for TSWV; high risk coupled with relatively high virus levels resulted in increased disease incidence. There are no new miracle treatments for thrips or TSWV in 2023, but we can do a very good job of managing both by using a combination of practices (found in Peanut Rx) that minimize risk.

Planter Preparation – Simer Virk and Wes Porter, UGA Precision Ag specialists

This is a perfect time for growers to check their planters and perform any required maintenance to ensure they are field-ready and dialed in for peak performance. While some of the planters are currently being or may have already been used to plant corn, it’s important to note that some planter settings will need significant changes for peanut to ensure accurate metering and seed placement. Negligence towards proper planter setup can quickly become costly by resulting in inadequate stand establishment. A checklist is available here (Planter Checklist) to perform a thorough planter inspection. Here are few other considerations related to planter setup and in-field checks when getting the planter ready for planting peanuts:

1. Seed depth – Recommended seed depth for planting peanuts is 2.0 to 2.5 inches. Verify seed depth before planting both on a hard surface and in the field. Mechanical seed depth settings can vary among the row units on the same planter so take the time to check planted seed depth for each row unit and make necessary adjustments. This is important as even small deviations in the depth settings across the planter can result in large, actual planted seed depth variations in the field.
2. Downforce – Proper planter downforce is important to achieve target seeding depth so make sure the downforce system (whether utilizing mechanical or an active system) is set to apply adequate downforce on each row unit. A downforce of 100 to 200 lbs is generally considered adequate for planting peanuts in most of Georgia soil conditions. Remember these downforce requirements can vary with soil type, texture and moisture so adjust downforce settings as needed when moving from one field to another or within the same field if needed.
3. Seeding Rate – Recommended seeding rate for peanuts is 6 to 7 seed/ft, which is higher than the nominal seeding rates for corn and cotton (2 to 3 seed/ft), and requires the seed meter to meter seeds at a considerably higher speed (rpm) even at normal planting speeds (3.0 to 3.5 mph). Therefore, it is important to ensure that the seed meter is setup and functioning correctly to attain the desired seeding rate during planting. Unnecessary skips or multiples will result in poor or uneven stand establishment, which can further impact yield if stand is reduced significantly. Also, since peanut seeds are larger than corn and cotton seeds, they require a higher vacuum, thus adjust the vacuum appropriately for proper seed metering.
4. Seed Placement and Seed-to-Soil Contact – Proper setup and functioning of row-cleaners (when planting in conservation systems), double-disc openers, gauge-wheels, and closing wheels for field conditions is critical for attaining adequate seed placement and proper seed-to-soil contact. Ensure that the double-disc openers are creating a true V-shape furrow, gauge wheels are running tightly (but not rubbing excessively) against the double-disc openers, and
   closing wheels are aligned perfectly behind the planter and set to apply adequate pressure on the furrow. Check for any misalignment of closing wheels and improper furrow formation when doing field checks and make necessary adjustments.
5. Planting Technology – Issues with planting technology during the planting season are common and can cost both significant time and money. Perform a thorough and timely inspection before planting to check the status and functioning of all technology components including GPS, seed monitor, wiring harnesses, seed tube sensors, rate control module, electric seed meters, and active downforce system (if available) as well as for any subscription or latest firmware updates for the GPS and the in-cab display.

Peanut Variety Update – Dr. Scott Monfort, UGA Peanut Agronomist

I have received several calls over the last few weeks regarding varieties. There a few key things to remember. First, a majority of the acres will still be GA-06G. Other varieties with some acres will be GA- 12Y, GA-16HO, GA-18RU, GA-20VHO, TifNV-High OL, AUNPL-17, & FloRun 331 (See figure below). There are seed increase acres out there this year for GA-21GR, TifNV-HG, and GA 22MPR. With this said, remind your growers that if they want to plant in April they need to look over the Peanut RX and do everything they can to minimize TSWV. There are only a couple of varieties with higher levels of resistance to TSWV compared to GA-06G: which includes GA-12Y and TifNV-High OL. We are hopeful the new varieties will provide some better resistance to TSWV. We will know more after this season. At this point all we can do is uses planting date, insecticide, row configuration, plant populations and tillage along with the current variety options available to minimize the impact of TSWV. I understand growers cannot adhere to all of the recommended cultural practices. We just want them to consider the recommendations and modify the practices as needed for their operation.

Along with these practices, growers also need to pay attention to seed quality and environmental conditions as they can affect final stand. The main thing of concern this year regarding seed quality is the potential reduction in seed vigor due to quality issues last year. Low seed vigor alone can cause slower plant emergence and/or skippy stands resulting in an increased risk of TSWV infection. However, if couple lower seed vigor, subpar environmental conditions, and planting in the high-risk window (AprilMay 10), you will have a prefect storm for having a high level of TSWV Infection and potentially a loss in yield potential.

Variety Information

• Georgia-12Y
  • Plant before May 12
  • Manage vines
  • Manage Rhizoctonia Limb Rot
• Ga-18RU
  • Higher susceptibility to TSWV compared to GA-06G
  • Do not plant before May 10ᵗʰ
  • Leafspot late in season can be an issue
• GA-16HO
  • leafspot late in season can be an issue
• GA-20VHO
  • High Risk to shed pods in prolonged periods of excessive moisture late in season,
    only plant in well-drained fields!
• TifNV-HG
  • Root-knot resistant
  • Similar to GA-06G in yield potential
• Ga-21GR and GA-22MPR
  • These two varieties are new and we have little information available
  • GA-21GR has potential for higher grades and medium to large seed size
  • GA-22MPR is a high oleic RKN resistant variety and is medium to large seed size

All About the Pod – produced by Macie Wheeler, UGA Graduate Student/Worth County Ext. Assistant

The latest episode of the “All About the Pod” podcast is now available. If you haven’t heard about it, you have missed out; but don’t worry, you can also go back and listen to past episodes. In Episode 21, Macie and Dr. Monfort visit with Dr. Tim Brenneman about New Seed Treatments and Cooler Temperatures. Go to All About the Pod to listen.

If we can be of assistance at Worth County Extension, please let us know.