Rain, rain, rain. This has been the story for the past week. Rainfall amounts for the past week have ranged from 3 inches upwards to 8 inches. Wet conditions are making weed control in cotton and peanuts, and nitrogen applications in cotton a challenge. The cotton crop ranges from early emergence to 12 leaf. Aphid populations are starting to build in area cotton fields and some reports of plant bugs.
Corn: Southern corn rust was confirmed today (June 21, 2023) in Clinch and Grady counties. As of June 22, 2023, no Southern rust has been confirmed in Colquitt County. The local corn crop ranges from VT to early dough. The current weather conditions are favorable for spread. We will likely find more rust soon. Growers who have sprayed a fungicide with mixed mode of action should get about 3 weeks of control. Will there be a need for a grower to spray a second time? Hopefully not but factors such as a) proximity to confirmed rust find, b) time since last application, and c) time remaining until hard-dough stage must be considered.
Pecan Crop Update by Lenny Wells — This is the time of year when I begin to get asked “What’s the Georgia crop going to be this year?” . That has always been a loaded question and I have come to the conclusion that there’s not a lot of good found in throwing a number out there. At best, its an educated, but still largely, a wild guess. So I am not going to put a number on the crop. What I will tell you is that the 2021 crop, according to USDA numbers, was officially 88.6 million lbs, the 2022 crop was 125.5 million lbs. Based on what I see out there, the 2023 crop set would fall between these two. It looks bigger than the 2021 crop and nowhere near as large as the 2022 crop. However, we are seeing tremendous scab pressure at the moment and it is happening at the worst possible time for the pecan crop. Almost daily rainfall for the last week and a half and rain forecasted daily for as far out as we can see during June as the nuts begin rapidly sizing is a recipe for disaster on susceptible varieties. This will almost assuredly lead to additional scab losses for the Georgia crop. The other thing that plays into the size of the crop is the vast pecan acreage we’ve planted over the last 13 years or so. Many of these orchards, even those planted 6-7 years ago are contributing significantly to the state crop now so if you are a grower who’s acreage is composed largely of old trees, which seem to be off across the state for the most part, you are going to think its a bad off year. We need to recognize that the younger trees are carrying the weight for the Georgia pecan crop now and this shifts our scale upward for both on and off years. Also, pecans are a global market at this point. The size of Georgia’s crop still certainly matters to the market and where prices fall out but with Mexico and South Africa in the picture, it doesn’t set the tone for pecan prices as much as it once did. Some people may take issue with this, but its a fact whether we like it or not. At this point the Georgia crop size is going to be determined by the amount of scab we end up with and how well growers are able to control the disease. READ MORE
Peanuts: This episode discusses the wet weather influences disease management, soil moisture sensors, insect management, and weeds. Enjoy.
Episode 29 — Management Decisions in Wet Situations
Peanuts in this area range from 14 to 60 days old. The first fungicide application has been delayed in some fields due to the wet weather. What do we do about disease management in peanut? Dr. Bob Kemerait has a few points about the current peanut disease situation.
Many growers have or should be starting fungicide programs for leaf spot control. Conditions now are near-perfect for the start of leaf spot epidemics. rain splashed spores from the soil and debris to the leaves, initiating infection, as does the prolonged leaf wetness periods. Also, fungicides may not have adequate time to dry between rains IF the grower can get back into the fields. My suggestions are as follows:
- 25-30 days after planting and can get in the field? Important now to put a fungicide out for most growers. Given our conditions, though 1.5 pt/A of chlorothalonil is good, even better to mix some other fungicide with curative activity, examples include Alto and Dormark, to improve efficacy.
- Growers at this time can also use Aproach Prima and Absolute Maxx. These are appropriate fungicides but I do not like to see either used under too much leaf spot pressure.
- Growers who are 40 days or beyond and need to apply their FIRST fungicide:
- Leaf spot is the main threat now, though we are always aware of white mold. Cooler temperatures and heavy rains have likely slowed the development of white mold.
- Lucento and Priaxor are fungicides that come to mind in this situation- good leaf spot control and some white mold activity. They work well for applications in the 45-day after-planting arena.
- Now would not be a good time for chlorothalonil alone. I would proceed with extreme caution before using selections from “a” and “b” above. In doing so consider Peanut Rx. If you are at a “high” risk for leaf spot, do not do it. If you are at “moderate” risk” for leaf spot, consider what could happen if you cannot make a timely fungicide application in 2 weeks.
- Application of Excalia + a leaf spot material or Elatus + a leaf spot material could go out at 45 days, however, given our current conditions I would rather see you save these guns (as with our other strong white mold products) for 60 days after planting.
Peanut weed control: Weeds are starting to be a common site in peanuts field due to the wet weather. Eric Prostko, UGA Peanut Weed Specialist, has some tips to hopefully avoid a bad situation.
What’s my best peanut weed control recipe for a disaster field?
a) Apply Select 2EC (clethodim) @ 8-16 oz/A + COC @ 1% v/v then
b) 3 days after the Select application, apply the following combination: Cadre @ 4 oz/A + Cobra @ 12.5 oz/A + 2,4-DB @ 16 oz/A + any Group 15 herbicide (either Anthem Flex @ 3 oz/A or Dual Magnum @ 16 oz/A or Outlook @ 12.8 oz/A or Warrant @ 48 oz/A or Zidua SC @ 2.5 oz/A). Include NIS @ 0.25% v/v when using Anthem Flex, Warrant, or Zidua.
c) Costly for sure but desperate times require desperate measures!
Can I also add Strongarm to that mix?
Yes, I did that in 2022 to clean up a peanut field and observed no major problems. Check out the following pics:
Can peanut herbicides be applied aerially by plane or drone?
The short answers is yes (but not Cadre. It does not have an aerial application label) but I have some concerns. I have been conducting weed control research since 1987. During this 36 year time frame, I have never applied herbicides in water volumes less than 10 GPA. Coverage, crop injury, and efficacy are my concerns. There is a ton of work being conducted with drones but I have not seen a sufficient amount of replicated university data to confirm true weed control efficacy. But in this current rainy situation, perhaps something is better than nothing??????
What are the minimum labeled GPA requirements for aerial applications of peanut herbicides?
Butyrac 200 (2,4-DB) = 5 GPA; Cobra = 7 GPA; Gramoxone = 5 GPA; Select = 3 GPA; Storm = 5 GPA; Ultra Blazer = 5 GPA
Is Classic still available for late-season Florida beggarweed control in peanuts?
Yes! Check out page 224 in 2023 UGA Pest Control Handbook for updated information about peanut cultivar tolerance to Classic.
Is Gramoxone (paraquat) still labeled for use in peanuts in a non-selective applicator such as a rope-wick or weed wiper?
Yes! Check out page 224 in 2023 UGA Pest Control Handbook. Gramoxone applied in this fashion is very effective on Palmer amaranth, Florida beggarweed, and sicklepod.
If you have questions please contact you local county Extension agent.
Have a great week.
Jeremy M. Kichler
Colquitt County Extension Coordinator
The University of Georgia Cooperative Extension does not endorse or guarantee the performance of any products mentioned in this update.