June Peanut Grower Magazine Jordan Column Peanut Notes No. 52 2020
In June growers continue to implement strategies to control weeds and prevent thrips from causing injury. Hopefully, in-furrow systemic insecticides have provided adequate control, and follow up sprays of insecticide have been made to clean up thrips infestations. Depending upon weather conditions, residual herbicides applied at planting or early postemergence have been effective. If not, matching the correct herbicide with the weed complex is critical, and making timely applications is required to effectively control of weeds. A good practice is to include more residual herbicide with the contact herbicide in a single application, especially in fields that routinely have weed issues throughout the season. The contact herbicides control escaped weeds that have emerged and the residuals prevent other weeds from emerging for several weeks. In most instances contact herbicides (paraquat plus Basagran, Cobra, Ultra Blazer, Storm) can be mixed with residual herbicides (metolachlor products, Outlook, Warrant, Zidua, Anthem Flex.) Keeping peanuts weed-free for the first 6 weeks is important in capturing yield potential. Minimizing thrips injury, especially in the upper Virginia-Carolina region also maintains yield potential. For Virginia market types and large-seeded runners, applying gypsum at flowering is an important input. Addressing any micronutrient deficiencies (boron and manganese) ensures optimal plant nutrition. Keep an eye out for yellow peanuts and determine the cause. Sometimes this is from wet conditions and poor root growth. At other times it can be a sign that nodulation is not effective and the plants need nitrogen. If a nitrogen deficiency is in place because of inoculant failure, getting applied nitrogen to plants as quickly as possible is a must. It won’t be cheap but it will be important to maximize yield. Take a look at the southern corn rootworm index while making decisions on applying chlorpyrifos. When you need it – you need it. If you don’t need it, an application of this insecticide can do more harm than good (flaring spider mites.) The major task at hand for the mid and latter portion of the season is establishing a solid leaf spot and stem rot fungicide spray program. Protecting peanuts from the pathogens that cause these diseases starts early. In North Carolina, applying fungicides at R3 to start protection from these pathogens is important. Then, make applications at 2-week intervals or possibly extending those intervals based on weather-based advisories. Rotating chemistry and making sure fungicides are applied at the correct rate, on time and using the right equipment are essential elements of an effective disease management strategy. Each state has a lot of good information on fungicide programs, and growers and their advisors are encouraged to spend time putting in place an effective program. Keep in mind that we have a significant number of cases where certain groups of fungicides are no longer effective. Make sure you are covered with the most effective chemistry each time you spray. In this column I seemed to use the word “important” quite a lot. There are a lot of important things to do in June, and doing them on time helps set you up for optimum yields this fall.