A website from UGA Cooperative Extension

News, events, and happenings in Colquitt County agriculture.

In this issue: EPA Comment Period for Organophosphates.. Peanut Update, How do I control tropical spider wort? Mr. Kichler, I have morninglory taking over my peanuts do I have any control options? Forage update: Leaf rust and armyworms….

EPA Comment Period for Organophosphates.. A NGO group is currently petitioning the US EPA to revoke all food use tolerances for the organophosphate class of chemistry. In peanut this means phorate (Thimet) and acephate (Orthene). This is not a good situation.

The comment period is open until September 25, 2022. Click HERE to visit the EPA website to review other comments and to add one of your own if you so choose. Click on Comment under Petition to Revoke Tolerances and Cancel Registrations for Certain Organophsphate Uses to enter your comment.

Losing Thimet would be a major blow to our efforts to reduce the impact of tomato spotted wilt disease.

Peanuts: Peanut maturity clinics have been busy this week. Since September 1, 2022, samples for dryland Georgia 06G have been averaging 143 days for dryland and 142 days for irrigated environments. Remember that each field is different and the optimum maturity can range due to environment.

How much yield loss do I have if I dig too early or too late?  Time of harvest is one of the most important decisions growers make each year.  Peanuts may lose 300 to 500 lb per acre and 2 to 3% in grade during the week and a half before optimum harvest.  Even greater losses may occur if harvest is delayed past optimum maturity.  Table 1 below illustrates the average loss over several years from digging too early or too late.  Dollars lost represent losses in clear profit, as no additional input is required other than digging at the optimum time. 

During hull scrape time, I will get a question or two about “What are these black freckles on my peanuts?”   According to Bob Kemerait, UGA Plant Pathologist, the black freckles and sometimes broken pegs are caused by lesion nematodes and are often considered a “cosmetic” issue. 

Lesion Nematode damage on peanut, Colquitt County, September 2022 -Kichler

How do I control tropical spider wort? I have received numerous phone calls about controlling tropical spiderwort after corn harvest. Below are a few words from Dr. Eric Prostko on this subject.

  1. Field corn growers should be reminded that post-harvest (if it ever stops raining in some locations) is a great time of the year to get a handle on Benghal dayflower/tropical spiderwort. Herbicides of choice include Gramoxone (paraquat), Aim (carfentrazone) and/or 2,4-D. Check out page 74 of the 2022 UGA Pest Control Handbook for more info and peruse this old poster (click on pics to get a better/clearer view). POSTER
    2) https://extension.uga.edu/content/dam/extension/programs-and-services/integrated-pest-management/documents/handbooks/2022-comm-chapters/Corn.pdf

Mr. Kichler, I have morninglory taking over my peanuts do I have any control options? I am glad you asked this question. According to Dr. Eric Prostko, peanut growers can also use Aim for late-season morningglory dessication about 7 days prior to digging.  Check out page 224 of the 2022 UGA Pest Control Handbook.  Remember, Aim is not very effective on smallflower morningglory and will cause some cosmetic (i.e. non-yield robbing) peanut leaf injury.

Forages: I have noticed leaf rust in a couple of Alicia bermudagrass hay fields last week. The causal fungus of leaf rust, Puccinia cynodontis, appears late in the summer when the humidity is high. Heavy infestations can decrease both hay yields and quality. There are four management practices that decrease the risk of disease infection, including: a) using a resistant variety b) maintaining soil fertility c) burning bermudagrass fields prior to spring green-up and d) harvesting forage in a timely and appropriate manner. If you would like more information on this subject please go to this link..

Rust in bermudagrass hayfield, Colquitt County, September 2022 — Kichler

Armyworms!! I have received a call or two about armyworms in hay fields. The life cycle of an armyworm is interesting. Armyworms cannot tolerate the winters in Georgia. The moths migrate from Florida, south Texas, and South American each spring and summer. Moths become active in the evenings and have an average life span of 2 to 3 weeks. The female moths lay eggs at night. The majority of eggs are laid 4 to 9 days after the female emerges from the pupal stage. These eggs hatch within 2 to 4 days after being laid by the moth. Armyworm moths prefer light-colored surfaces to lay eggs. In pastures and hayfields please evaluate places such as fence rails and posts and tree limbs for eggs.

Armyworms are most active in the early morning or late afternoon when temperatures decrease. They can hide in the thatch and topsoil layers during the hotter parts of the day. Armyworms have six stages of larval development. The mature larvae eat more than all other ages put together. During the summer, caterpillars feed for about 14 days. It is interesting to note that the largest amount of feeding is in the last four days which occurs when the caterpillar molts into its largest size. The fully-grown larvae then burrow into the soil and form pupae. Ten days after the larvae burrow into the soil, the moths emerge. Economic treatment thresholds are three armyworm larvae per square foot in hayfields and pastures. Young larvae are much easier to kill than adult armyworm larvae. Several insecticides are available to control armyworms and please consult your local county Extension agent for options. Please pay careful attention to grazing or pre-harvest intervals of the product used for armyworm control.

If you would like information on insect control in perennial forages please go HERE

Below is additional information about insecticides used for armyworm control in forage production systems.

If you have any questions or comments please contact your local county Extension agent.

Have a great day,

Jeremy M. Kichler

Colquitt County Extension Coordinator