Late June and July bring a transition from controlling weeds and thrips to putting in place a solid fungicide program of leaf spot and stem rot. In the upper V-C Region we do need to keep our eyes out for Sclerotinia blight, but virtually all farmers need to protect peanuts from leaf spot and stem rot. It is possible to have outbreaks of tobacco budworm, corn earworm and fall armyworm, but infestations can be erratic. Thresholds are in place for these foliar-feeding insects.  It is also possible that we will have spider mite outbreaks to contend with.

In our part of the woods, we generally have a 5-spray program of leaf spot. We recommend that you start and finish with the multi-site fungicide chlorothalonil (sprays 1 and 5) with combinations of fungicides for sprays 2, 3, and 4 that control leaf spot and stem rot. If you have fields with Sclerotinia blight, consider including Miravis and Elatus for sprays 3 or 4. In fields with high levels of this disease, sequential sprays are likely warranted. Historically, this decision was much more challenging because Omega 500 (fluazinam) was expensive and did not control leaf spot. The mixture of Miravis and Elatus offers protection of all three diseases. With respect to leaf spot, practice resistance management for sprays 2, 3, and 4 by rotating sites of action. There are numerous ways to protect peanuts from leaf spot and stem rot without selecting for resistance. We encourage farmers to use our leaf spot and Sclerotinia blight advisories. These tools can help you avoid unnecessary sprays but also take the guess work out of the decision. Sometimes we think we don’t need to spray because it has been a while since we had rain. However, dew points may be high enough to encourage disease development even when we feel like we are close to being in a drought. Be timely with sprays when they are needed and use the recommended rates for each fungicide.

There will be some weed escapes in many fields as we move through July and August. Make sure you are within the preharvest interval for products. With the exception of grasses and some broadleaf weeds, mid-season and late season herbicide applications will in most cases only suppress weeds. However, this can make a big difference when digging and inverting vines and can reduce contributions of weed seed to the soil seedbank.

In the V-C region, prohexadione calcium (Apogee, Kudos, and Cryova) is often sprayed beginning in the middle of July when peanuts are lapping in the middles. Apply this product at 50% of laterals from adjacent rows are touching. A second application can be made 2-3 weeks alter depending on regrowth. The new liquid formulation of Kudos performs well but use caution when applying with other plant protection products. Depending on the tank-mix partner, Kudos OD can burn peanuts. A key for the next two months is to keep vines as healthy as possible. This will help optimize yield in general but will also give us the greatest flexibility in digging.