A New Multi-crop Update from UGA Plant Pathologist-Dr. Bob Kemerait

I appreciate Dr. Kemerait sharing his thoughts and recommendations with me on crops he has state responsibility for and allowing me to provide his insights to you.  All within the quotes are directly his thoughts.  He is sharing his email to Georgia’s Extension Ag Agents and a few others such as our association.  I will add a few thoughts at the end including some from Dr. David Buntin, UGA Entomologist. Also, please pay attention to bullet point 6 from Dr. Kemerait.

“Greetings-This is the week.  The week where (for now) there aren’t storms on the horizon and where even though it will be a little cool in the morning, many growers will be, can be, pushing ahead to plant cotton, peanuts, and maybe soybeans.  Many growers I have talked to are frustrated at “being behind”, so you know they are going to get after it this week as soon as they can.”

  1. ” They will get ONE chance in fighting seedling disease in their crops, which is especially important for peanuts and cotton.  The risk of seedling disease is a summation of contributions from soil temperature and moisture at planting, weather forecast over the next week, or so, tillage (higher risk in reduced tillage), crop rotation, variety planted (some varieties are slower to germinate and lower vigor), and seed quality (poorer quality seed are not only more likely to harbor pathogens but are also likely to be lower in vigor).
  2. Fighting seedling diseases requires integrating an assessment of environmental conditions before choosing “the planting date” and use of a solid fungicide seed treatment.  Additional options include extra seed treatments and in-furrow fungicides.  REMEMBER:  “one size does NOT fit ALL! ” While ALL cotton and peanut growers will need a base fungicide treatment on their seed, some, but not all, will also need the “extras”.  As another example, while cotton growers will benefit from use of azoxystrobin in-furrow for management of the primary pathogen, Rhizoctonia solani, peanut farmers will face primarily Aspergillus niger and possibly Rhizoctonia. Azoxystrobin is less effective against Aspergillus and other products, like Proline and Velum Total may need to be considered where threat from Aspergillus crown rot is high.
  3. As with seedling diseases, growers get truly one “best chance” to fight nematodes.  Peanut and cotton and soybean producers can choose to plant root-knot nematode varieties.  If there nematode problem in the field is something other than root-knot, or if they plant a root-knot-susceptible variety, then they need to use a nematicide.  NEED TO USE A NEMATICIDE.  You can’t go back and fix it…. ask some corn growers this season who already see the damage to their fields from stubby-root nematodes….
  4. Its been fairly cool over the past couple of weeks, but note that that early-season white mold is FUELED by short rotations, adequate soil moisture, and hot early season conditions.  For this reason, growers should be prepared to “pull the trigger” early if threat to while mold rises.  “Pullling the trigger” may mean banding Proline at 3-5 weeks after planting.  It may mean using at white mold fungicide at 30 or 45 days after planting.  It may mean using Proline in-furrow at planting, but NOTE: Proline in-furrow is most beneficial for CBR control, control of Aspergillus crown rot, and some, but not great control of early-season white mold.  Proline is an excellent fungicide, but I would be VERY careful in deciding to spend the money at planting on Proline if ONLY hoping for extra white mold control.
  5. Tomato spotted wilt on peanuts is another “one chance” disease and then “you sleep in the bed you made”.  (It drives non-native English speakers crazy talking to me because I like to use idioms…)  Please direct your growers to the excellent Peanut Rx resources displayed prominently on the UGA Peanut Team website, to include A) the full index, B ) Peanut Rx programs for various participating companies, and C) An automated Peanut Rx calculator.
  6. Watch the corn crop- early planted corn is now reaching stages where a fungicide application COULD be justified if northern or southern corn leaf blights are threatening.  Before deciding to spray, or not, it is critical to scout the field.  Most growers will not need a fungicide until tassel, but some will….. 

A few thoughts from me.  I encourage all corn growers to walk your fields as often as possible.  Most people involved in agriculture in Georgia recognize that this is always an extremely busy time in Georgia agriculture even without the issue of COVID-19.  To maximize the investment you already have in corn, please take the time to scout and walk your corn fields in order to protect that investment. That goes for all your crops. Indeed, you may see some things that can inform you of some of your decisions you have made and, allow the computer on top of your shoulders to contemplate and review and weigh that decision.  A lot of decisions we make have trade-offs.  That is life, of course.  Walking your fields routinely or having some one walk your fields and provide detail reports is very important.

The following example happened today.  A consultant this afternoon was gracious enough to share the photos of a corn field in Worth Co. as he was scouting.  The hybrid is a good yielding non-Bt hybrid.  It surprised me a little as I don’t often see this much worm damage in a V12- V13 stage corn crop.  Worms at this stage really don’t warrant spraying because of the difficulty of getting enough insecticide to the insect to provide good control, and typically a high percentage of the field must be infested to warrant such measures.

damage indicative of true armyworms

I talked to Dr. David Buntin, UGA Entomologist that conducts entomological research in corn and sorghum and he has received questions the past couple of weeks regarding infestations in small grains and corn. He spoke about infestations that are occurring not only in Georgia but Alabama and Mississippi.  He mentioned that this is the time of year that we typically see infestations from true armyworms. He also reminded me that while this was not a bt corn hybrid, resistance in european corn borers, corn earworms/bollworms (and I my guess….others) is building to the genes used in many corn hybrids and cotton varieties.  The best resistance for borers, earworms and armyworms are found in corn hybrids that are stacked with the Vip genes. For more details on this and other insect control, go to the following url: https://grains.caes.uga.edu/content/dam/caes-subsite/grains/docs/corn/2020-Corn-Production-Guide.pdf and scroll to ~ page 35 to “Insect Control in Field Corn” authored by Dr. Buntin.  There you will find very useful information.

While on this subject of the corn production guide, I will refer you back to Dr. Kemerait’s bullet 6.  Within this same publication, he has outstanding recommendations and thoughts on corn disease management.  Routinely scouting your fields will help you discover any early disease infections, get you in front of it, and give you the chance to protect your yield potential and maximize your profits.

damage indicative of true armyworms.

 

Stay healthy and stay safe.  You are important. Try not to let stress tear you down.  Talk to a friend, a confidant….someone who shares your love for this great profession that we are all involved in some way.  We are made to protect and nurture, living on optimism and faith.

 

 

 

 

 

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