David Jordan

V-C News Fall Column 2026

As we move into late August and September, digging and harvesting are on our minds. Part of this preparation needs to make sure peanut plants are as healthy as possible going into the digging phase of the crop. I know many growers tire of hearing me talk about how important it is to let peanuts reach optimum maturity before you dig. I get that. I get tired of hearing it too, and it seems like in the fall my life revolves around that basic principle. Regardless, here’s the reminder. On the front end of optimum maturity, you gain approximately one percent yield for each day you delay digging up to optimum maturity. In the graph, you will see that when you dig 28 days before optimum maturity, you only realize 72% of maximum yield. That is an obvious interval to avoid. The same can be said for 14 and 21 days. When we get to a week or 10 days before optimum maturity, sometimes we convince ourselves we need to get started. There are a lot of reasons to jump the gun on digging. I don’t push too hard on those discussions. I know it is stressful and I don’t know what’s going on with the details on a farm. But what I try to do is point out what the outcome is most likely to be with early digging. That’s where the graph comes in as well as the digging evaluation tool on the peanut extension portal (https://peanut.ces.ncsu.edu/peanut-digging-evaluation-tool/).

Much of the time we only give you half of the story, at least in the moment. The graphic in the digging evaluation tool does a good job of showing the benefits of digging at optimum maturity and the financial cost of digging too early. Greg Buol in our department helped create the tool and did a great job of doing so. However, the other side of maturity is also a concern. This is not in the current digging evaluation tool, but we are working in that direction. What happens if you patiently wait for peanuts to mature before digging and then experience delays? The potential ramifications are real – pod loss due to pod shed if digging is delayed and the thought of dancing around wet fields and frost potential can make the fall stressful. We are in our fourth year of getting a better handle on the relationship of digging date and leaf spot disease after peanuts reach optimum maturity. The yield loss in those trials when the canopy is full of lesions and defoliation is around 40% at optimum digging was not surprising. We lose about 2.1% of yield per day after optimum maturity when we start with this much disease, based on these trials. However, I was surprised to a degree when disease was not present or present at a modest amount. Yield held up rather well through 4 weeks after optimum maturity. An eleven percent yield loss four weeks after optimum maturity was less than I expected in absence of disease. It also turned out that if canopy defoliation stayed below 40% throughout the digging cycle (in this case through early November,) yield decreased by about 11%, even though disease control was not perfect. This surprised me as well. I was anticipating the curve with 15% lesions and no defoliation to be halfway between no lesions and 100% lesions at optimum maturity. Plots with about 50% of leaves with lesions at optimum maturity would have been informative. One caveat in this work is location. Once we get into October in northeastern North Carolina, temperatures moderate and this can slow the progression of disease. I suspect it the trial was conducted in Whiteville, digging loss with 15% and not defoliation at optimum maturity would be more extreme. We might bet to the 40% defoliation threshold more quickly.

What’s the takeaway? The story is still the same prior to digging. About a 1% per day decrease in yield when you dig on the early side. The results after optimum maturity remind us of how important an effective fungicide program is in protecting yield. Of course, few people would not spray fungicides. But we do run into issues when fungicides are not applied in a timely manner or when the ones used are less effective due to any number of reasons. There are a significant number of fields around the state that have close to 100% of the canopy with lesions and defoliation approaching 40% before or at optimum maturity even when fungicides are used. Determining why this happens is an important part of planning for the next season. There are also fungicide options that can help towards the end of the season if we have modest levels of disease, but these fungicides are not miracle workers.

The results from the trials mentioned above and shown in the graph can be found on the extension portal at the following link (https://peanut.ces.ncsu.edu/news/summary-of-digging-date-and-leaf-spot-management-trials-from-2023-2025-peanut-notes-no-283-2025/). The graph I created for this column is “cleaner” than the data slides in that post. It can be complicated from year to year, and in the true spirit of Jack Bailey, he would remind me that we are here to tell story, and he might say don’t let things like messy data stand in the way of a solid recommendation.

Circling back to the first sentence of this column. Do whatever you can to have healthy plants throughout the fall. This gives you tremendous flexibility when logistical challenges and adverse weather exist, and most especially where these two factors collide. In the table, you’ll see that the highest yield and highest %ELK occur when we let peanuts reach optimum maturity in absence of leaf spot disease.

A quick note on resources. At the link above, you can also find videos of pod blasting and how to use our maturity charts. There is also a video on how to use the digging tool to keep track of your samples and see how much you can make or lose based on your decision of when to dig relative to the prediction of when peanuts will reach optimum maturity.