Peanut Grower Magazine Column Peanut Notes No. 87 2023
El inglés es el idioma de control de esta página. En la medida en que haya algún conflicto entre la traducción al inglés y la traducción, el inglés prevalece.
Al hacer clic en el enlace de traducción se activa un servicio de traducción gratuito para convertir la página al español. Al igual que con cualquier traducción por Internet, la conversión no es sensible al contexto y puede que no traduzca el texto en su significado original. NC State Extension no garantiza la exactitud del texto traducido. Por favor, tenga en cuenta que algunas aplicaciones y/o servicios pueden no funcionar como se espera cuando se traducen.
English is the controlling language of this page. To the extent there is any conflict between the English text and the translation, English controls.
Clicking on the translation link activates a free translation service to convert the page to Spanish. As with any Internet translation, the conversion is not context-sensitive and may not translate the text to its original meaning. NC State Extension does not guarantee the accuracy of the translated text. Please note that some applications and/or services may not function as expected when translated.Collapse ▲
This is my July column for Peanut Grower Magazine. I’m posting it earlier just so I don’t forget to do so later on. I’ll emphasize some these points in future Peanut Notes.
Our primary focus is in July is establishing and maintaining an effective fungicide program for leaf spot and stem rot. In North Carolina, we recommend that the first spray be made at the R3 stage of peanut growth but no later than July 10. We typically have a 5-spray program in our area when considering two-week intervals. If you have a shorter rotation that may have more disease inoculum, starting the program a week or so earlier will minimize risk. We recommend starting with a chlorothalonil treatment either alone or with a tank-mix partner that has some curative activity. If you are closer to mid-July with your start, we recommend a fungicide treatment that also has stem rot activity. Sprays 3, 4 and 5 (if you start in early July) will need both leaf spot and stem rot fungicides. Numerous combinations are effective on pathogens that cause these diseases. The key is to stay on a 2-week interval for many of the fungicides you might apply and rotate chemistry for resistance management. Some fungicides will provide longer control than two weeks. The final spray should include chlorothalonil. In some years and depending on when you started your spray program, a sixth spray may be needed, especially if September is warm and peanuts are not going to be dug until sometime in October.
We have seen less and less Sclerotinia blight over the past decade but it is still out there. Resistance in our virginia market type varieties (Bailey II and Sullivan) is good for this disease. The exception is Emery but it is much better than the older varieties like CHAMPS and Perry. Depending on the fungicides you are using for leaf spot, you may be controlling any Sclerotinia blight you might have with those products.
If we get dry during July and August, keep in mind that rainfall is not always the best indicator of whether or not leaf spot will continue developing. We have observed significant leaf spot under drought (defined by no rain) if dew points are high at night. The leaf spot advisory can help you keep spraying when risk is high (and stop spraying when the risk is low.)
Our current thresholds for foliar-feeding insects (fall armyworm, corn earworm, and tobacco budworm) are relatively high. However, if you need to make an application, use caution, especially if it is dry and spider mites are building. If you use a pyrethroid, it is very likely mites will become more prevalent. Other insecticides can minimize the risk of spider mites and are more effective on pyrethroid-resistant individuals in the population (although they are more expensive.)
If it turns out we have good growing conditions, Bailey II and Emery (and in some cases Sullivan) can have excessive vine growth. Apogee or Kudos can help a lot here. The first spray goes out when 50% of vines from adjacent rows are touching. A second application can be made two to three weeks later if needed. Do not force the second spray. You will begin seeing regrowth and that is the time to make the follow up application. We can set peanuts back if we apply these PGRs under dry conditions or if we start the sprays too early. Always include nitrogen with these PGRs. There are many questions in July and August about tank mixing. There is not nearly enough room to address those questions here.