Last week was a challenging week. Rain slowed down peanut harvest. Drier conditions will be in the forecast this upcoming week. Dr. Hand, UGA Cotton agronomist, says the cotton defoliation recipe will be the same as last week. Statewide it looks like 80s for highs and 60s for lows. Similar recipe to last week – 3-4 Dropp, 10 Folex, 32-42 Prep. On Wednesday/Thursday when the highs are closer to 90 we can probably get away with 8 oz Folex. Check recs in the production guide for PPO inhibitors – I’d probably go with 0.75 oz Reviton, same for Aim, 1.5 oz ET, or 1 oz ETX. If your growers decide to use a PPO inhibitor, take Folex out of the mix and make sure to use the label recommended adjuvant.
Hull Scrape clinics will be held this week on Tuesday, and Thursday from 8:30 to 10 am at the Colquitt County Extension office. The hull scrape clinic will start at 9 am on Wednesday morning. If you need peanuts done at other times please call or txt me and we can arrange for those peanuts to be done. Last week, Georgia 06G were averaging 142 for irrigated and dryland was averaging 145+ days in the samples that were brought to the office. There has been some variability in dryland samples as some fields have a split crop due to unique weather that we had this year.
Table 1 below reminds us that harvesting at the optimum time can make peanut growers money. This data, compiled by Monfort and Williams, shows that by digging a week early, growers can reduce yields by approximately 200 lbs, and digging a week late can result in a 600 lb yield reduction.
I got morning glory in my peanuts!!! Since we are so close to harvest, our best option would be Aim at 1-2 oz/A. Apply 7 days before digging for the late-season desiccation/defoliation of annual morningglories (Ipomoea spp.). Aim is less effective on smallflower morningglory. Use in combination with either a NIS (0.25% v/v) or COC (1% v/v). Aim may cause peanut leaf spotting or burning. Use at least 15 GPA for optimum results. Do not graze or feed peanut hay to livestock. Only 1 application per season is permitted. Rain-free period is 6–8 hours.
When to dig early? I had a question or two about disease pressure and how that influences when to dig peanuts. It is not recommended to dig early due to spotted wilt no matter how much is in the field. If white mold is reaching 50% then we need to consider digging. Leaf spot defoliation reaching 60% will likely result in yield loss.
Colquitt County Corn Variety trial at the Sunbelt Ag Expo. This year, I had the pleasure of planting a replicated on farm corn variety trial at the Sunbelt Ag Expo. The hybrids include Dekalb 7045, Dekalb 6835, DG56TC44, DG 58TC94, Pioneer 1608, Pioneer 17677, Croplan 5760, Croplan 5893, Agratech 711, Agratech 85VP. NK 1402, NK 1402, Seedway 17A24, Seedway 14B24, Integra 6493 and 6641. This project would not be possible without industry support.
A multi-county farm corn variety trail was conducted in Terrell, Grady, Mitchell, Sumter, Thomas and Colquitt Counties this past year. Ten hybrids were evaluated from Agratech, Croplan, Dekalb, Dyna-Gro, and Pioneer. The yield data is in the table below. This project could not have been possible without industry support.
I want to start over and replant my bahia or bermudagrass hay patch. What do I do? According to the UGA Bermudagrass Production guide, renovation is required when more than 50% of the pasture or hayfield has thinned out, has exposed soil, and/or covered in existing noxious weeds. It is strongly recommended to rotate to an annual summer crop for at least one season before planting a new stand of bahia or bermudagrass. The best way to ensure the old stand and noxious weeds have been removed is from shading a competitive summer annual such as sorghum or millet. Multiple herbicide applications and/or tillage may be required as well. The existing material must be fully controlled before a new crop is planted to prevent contamination and competition. Failure to control the existing vegetation will most likely result in a failed establishment of the new planting.
What is the difference between diploid and tetraploid ryegrass varieties? I am glad you asked. Dr. Dennis Hancock, former UGA Forage Agronomist, wrote an interesting article about this a few years ago. Annual ryegrass is naturally a diploid species, meaning it carries 2 sets of chromosomes (2n). American scientists in the 1930s began experimenting with ryegrass hybrids and discovered mutants that had 4 sets of chromosomes (4n) but were substantially larger with wider leaves and stems. Researchers in the Netherlands expanded upon this early work, and ultimately, German plant breeders introduced the first tetraploid varieties into the U.S. in the early 1960s. Plant breeders have since developed many diploid and tetraploid varieties. Because the tetraploid varieties have larger tillers, wider leaves, and are simply bigger in general, they are impressive to look at compared to the diploid varieties (Fig. 3). Apparently, cattle think so, too. A grazing preference trial in Mississippi showed that forage provided by tetraploid variety plots was consumed 54% faster than diploid varieties. Yet, when researchers there looked at long-term yield data from their variety trial program, the yields of diploid and tetraploid annual ryegrasses were not different in most locations and only tended to give slightly more yield (less than 10%) in their southernmost location (Poplarville, MS). Further, when they conducted a grazing trial comparing diploid and tetraploid varieties, their stocker steers showed no difference in ADG or gain per acre. Their conclusion from all this research is that there is more difference within diploid and within tetraploid varieties than there is between them. So, look for a high yielding variety that is recommended for your area and disregard the ploidy level. One practical consideration, however, is that tetraploid seed is usually 50 to 100% larger than diploid seed (Fig. 4). Though there is no difference in the seeding rate recommendations for the diploid versus tetraploid varieties (20-25 lbs/acre if drilled; 25-30 lbs/acre if broadcasted), it is important to calibrate, check, and adjust the drill to account for these differences in seed size.
Figure 3 below shows differences in seed, leaf, and plant characteristics between diploid and tetraploid varieties of annual ryegrass (Rios et al, 2015. Crop Science 55: 2078-2090) and relative forage intake when beef cattle were provided a choice between diploid and tetraploid varieties († Solomon et al., 2014. Crop Science 54: 430-438).
Figure 4. Varieties of annual ryegrass differ in seed size, which will likely require adjustments to conventional and no-till grain drills to maintain the same seeding rate. Each of these beakers contains 20,000 seed of their respective varieties. Note that the seed of tetraploid varieties takes up approximately 50% more volume than the diploid varieties. Photo credit: Henry Jordan, UGA Statewide Variety Testing Program.
What about whitefly this week? The trap captures from Dr. Roberts show an overall decrease of whitefly captures compared to the week before. The trap data is below.
Tanner’s overall trap data mirrors the same trend, but some locations have seen a small increase. The table below illustrates white fly sticky trap captures from August 12 through September 10, 2024.
I had somebody ask about if I had any local data on winter annual forages. Last year, a winter annual forage demonstration was conducted at Packer Park Farm in collaboration with the Colquitt County Young Farmer Advisor, Heath Cross. This demonstration was planted on November 29, 2023, and consisted of 8 treatments, which are listed below. The seed was sponsored by Greenpoint Ag. Each treatment was planted in a single strip across the plot site with a grain drill. Rocky Herndon let us borrow the grain drill for this demonstration.
Dry matter yields were estimated by harvesting a square foot of forage in three areas in the plot at 67 and 90 days after planting. The samples were then dried down in a microwave, and yields were calculated on a dry matter basis. The second harvest reflects cumulative yield since the plots were not mowed during the demonstration. The yield data is in the chart below. A similar study is going to be implemented this fall at the Packer Park farm.
Irrigation Pond Herbicide Application Considerations – Braxton Crews, Webster County ANR Agent. As we near harvest season and begin terminating irrigation, we enter a critical timeframe for weed control in our irrigation ponds. Most aquatic herbicides perform best when water temperatures are at or above 60°F and there is still sufficient photosynthetic activity. Additionally, at or soon after harvest is an optimal time for herbicide application because we do not have to worry about irrigation restrictions. Below, I have included a brief table showing the irrigation restrictions on some common aquatic herbicide active ingredients. This table may also be useful for quick reference during the growing season next year.
Notice the difference in irrigation restrictions between some of these herbicide active ingredients. Like many things, irrigation pond herbicide recommendations are not one size fits all. There are two active ingredients on the table above that have irrigation restrictions of nearly 4 months, and they are not even options for some. I believe that we can easily control most weeds without using longer residual herbicides, but they are options if their labels are followed properly. Just to be clear, I am NOT telling every grower in Georgia to go and spray Imazapyr or Triclopyr in their irrigation ponds with weed problems. In fact, I would actually recommend that this be a last resort when other avenues have been exhausted, but it is an option nonetheless. For those growing small grains through the winter or those who rely on irrigation ponds for frost protection, this option is off of the table.
Let’s say we had a cotton or peanut field irrigated from a pond with a bad weed problem that was harvested before the end of September. If we went in on October 4th and treated the pond with something like Arsenal or Renovate, we would have to wait until February 1st, 2025 to be able to irrigate from that pond. For some of our folks down in deep South Georgia who start planting corn in February, they may not be able to apply these herbicides much past October 15th, which is why it is important to start taking care of this problem now. For those herbicides with shorter restrictions, it is still important that we start applying them in the fall after irrigation termination because we will get a better kill now while we still have acceptable water temperatures. If we rolled the dice and tried to apply them 5-30 days (depending on the product) before we started irrigation, we may or may not have the weed populations we would see later in the summer and we may or may not have water temperatures above 60°F. As far as in-season irrigation pond herbicide applications for next year go, I would imagine that any product that has a restriction longer than 7 days would not be a very good option, especially if we have droughts like we have had this year.
Have a great week,
Jeremy M. Kichler
Colquitt County Extension Coordinator
The University of Georgia Cooperative Extension does not endorse or guarantee the performance any products mentioned in this update.