Question, Persuade, Refer (QPR) Agribusiness Training Rescheduled!! The Question, Persuade, Refer (QPR) Agribusiness Training scheduled in Colquitt County on August 8, 2023 from 10:00 to 1:00 will be rescheduled for a later date. Stay tuned.
The Fall Vegetable Disease and Whitefly Meeting is scheduled for Wednesday, August 9. 2023. If you are interested in attending please contact the Colquitt County Extension.
Peanuts: It has been an interesting week for local peanuts. The peanut crop ranges from 60 to 110 days old. In fields that I have visited this week, tomato-spotted wilt seems to have appeared. Tomato-spotted wilt is being observed more and more lately. It is believed that the blistering-hot conditions over the last couple of weeks following a relatively cool and wet period have brought symptoms forward. The root systems of the peanuts that are damaged by TSWV can’t keep up. I had a grower or two ask the question, “We followed Peanut RX and we still have Tomato Spotted Wilt. Why?” According to Dr. Bob Kemeriat, “UGA Extension never said use of Peanut Rx will eliminate spotted wilt from your fields; we need an “immune” variety to do that. However, use of Peanut Rx allows farmers to grow peanuts profitably by reducing the risk, incidence, and severity of this disease as compared to not using it. It is another tough year for spotted wilt. But you know what? We can’t do anything now for spotted wilt in a peanut field.”
The picture is an example of a peanut variety that is susceptible (left) to spotted wilt and one that is resistant (right). Courtesy Dr. Bob Kemerait.
White mold has been another topic this past week. Conditions for this disease are near perfect. Growers must continue an effective, timely fungicide program. Dr. Bob Kemerait suggests that as we fight white mold with Elatus, Excalia, Umbra, Convoy, Fontelis, Provost Silver, and Teb, we not FORGET the necessity to ensure protection from leaf spot at the same time, whether it is mixing something like Alto, Domark, Provysol, or SPECIFIC sulfur or chlorothalonil with the white mold product (not always necessary) or using products like Lucento and Priaxor and a combination of sulfur, Alto, Domark, and chlorothalonil in bookend applications. We are in the toughest disease period for white mold and leaf spot on peanuts—late July through mid-September.
Cotton: The cotton crop ranges from late squaring to 6 weeks of bloom. Topics this week include spider mites, foliar diseases, and irrigation. Whitefly populations have increased this week around Colquitt County. Aphid populations seem to be on the rise this week. So often, aphids can be mistaken for whitefly nymphs.
Examine the underside of the detached leaf for the presence of immature whiteflies. Early-stage immature whiteflies are very difficult to see without magnification, but later (third to fourth) instars are noticeable without a hand lens. Small aphids, which are also pear-shaped and light in color, can be confused with immature whiteflies. If you are not sure, use a hand lens or a loupe and look for legs (aphids) or eye spots (whiteflies) (Figure 3). The forecast this week is for hit-or-miss showers. Rain events can compromise the accuracy of whitefly scouting, especially for adults. It is best to scout when plants are completely dry. If you want more tips on scouting whiteflies in cotton, go to the publication.Sampling and Managing Whiteflies in Georgia cotton
The current weather pattern is perfect for foliar diseases in cotton. I have seen low amounts of aerolate mildew and target spots this past week.
Corn: Corn producers are beginning to harvest their crop in Colquitt County, and so far I have been hearing some good yields. This corn crop has seen its fair share of difficulties such as hot, dry weather, hail and a very rainy weather pattern. We’re hoping for a safe and successful harvest season.
I have received a question or two about harvest aid applications for corn. Dr. Eric Prostko, a UGA Weed scientist, says that his usual recommendation is to apply a combination of Roundup and Aim. The PHI for glyphosate and Aim is 7 and 3 days, respectively, according to the Pest Control Handbook. This treatment will not miraculously remove the running morningglory plants, but it will desiccate them enough to facilitate harvesting (i.e., make the vines more brittle and less likely to wrap). See below for more specifics from the 2023 UGA Pest Control Handbook.
I have also found Southern rust and Tar Spot in Colquitt County corn that was close to the black layer. According to Dr. Bob, these diseases do not impact yield after the dough stage. Most of the corn in the county ranges from hard dough to black layers. Growers who planted late corn might have to watch the disease situation more closely.
Below is information from the UGA publication Reducing Aflatoxin in Corn during Harvest and Storage. Here’s an excerpt:
Research shows most Aspergillus infections occur in broken and damaged kernels and in foreign material. Damage to the grain seed coat permits the easy entrance of molds and fungi and promotes the rapid development of storage rots at high moisture and temperature levels. Heat and drought stress can cause seed coat fractures and increase the opportunity for infection to occur. Aflatoxin can develop within 24 hours in mold- and fungus-infected corn stored under these conditions, even though the corn was previously free of aflatoxin.
Harvesting must be done in such a way to prevent damage to the seed coat and to assure maximum cleaning of the grain, since damaged seed and foreign material contribute to the development of aflatoxin. The following practices will reduce the likelihood of this problem.
When corn reaches maturity, harvest immediately and dry mechanically. Harvest should begin when the moisture level reaches 28 to 30 percent. Studies have shown that most corn hybrids will normally lose about 0.5 to 0.6 percent of their moisture per day during the dry-down period. You can reduce field exposure by at least 1 to 2 1/2 weeks by harvesting above 22 percent moisture compared to letting corn dry in the field at 15 percent or less. This will require immediate drying, however. READ MORE
Soybeans: I got a question or two about soybeans this week. I have received this question a couple of times this week from growers and retailers with indeterminate soybeans. According to the soybean weed control section of the 2022 UGA Pest Management Handbook, paraquat can be applied to soybeans based on the following instructions: The paraquat rate according to this reference is 0.25 lb ai per acre, which is 16 oz of a 2 lb formulation. READ MORE
Please be careful this week in the heat. 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.