Realities at Harvest

David Jordan

As we move through August, looking back, we see that the peanut crop in North Carolina has improved from the drought conditions in June. In some areas, we had more rain than we needed in July and early August. In some cases, weather in July kept us from being timely with fungicide sprays. The ramifications of some of those delays, along with challenges in applying prohexadione calcium (Apogee, Kudos WDG, Kudos OD, or Cryova) in a timely manner, may have an impact on yield in the fall. The old saying, “a dry year will scare you to death but a wet year will kill you,” was said by a number of folks this year (I think that was a reference to weed control, but maybe disease control too.) However, generally, we have a very good crop in the field if we can get it harvested. Here are some points about digging and harvesting that need to be considered.

Healthy vines

One of the most important things we can do, to give us the greatest flexibility in when we dig pods and invert vines, is to have plants that are healthy. This generally means having a robust and appropriate fungicide regime for the conditions we experience. When we have disease, especially leaf spot, we can be forced into digging prior to optimum maturity due to pod shed. Our rule of thumb is that we begin seeing measureable yield loss when we are at about 35% defoliation. At this level of defoliation, it is likely that all of the leaves on the plant have lesions, and in short order they will almost all fall off of the plant. With both incidence (leaves with visible lesions) and defoliation (leaf drop), we double the magnitude each week. Of course, this depends on weather conditions, but generally, we will go from 10% to 20% incidence or defoliation in one week. Next thing you know we are at 40% a week later and then 80% the week after that. When we have disease lurking in the canopy in late August or early September, plant health can fall apart quickly. It can happen so quickly that we cannot get fields with disease dug and picked rapidly enough to prevent additional yield loss. The key is to have a good spray program throughout the season and maintain sprays through September if needed to keep epidemics at bay. That will give you the greatest flexibility in getting across acres with minimal pod loss.

One important thing to note is a misleading statement on the peanut profile board about disease. I wrote that once you get to about 20% of leaves with visible lesions, it is likely that most of the rest of the canopy is already infected. That is an accurate statement. However, then I wrote that a fungicide application will likely be of no benefit in protecting peanuts from leaf drop and pod shed, I was thinking about chlorothalonil, as this fungicide is what we recommend as the last spray for resistance management and protection just before we dig. The statement is true if that is your fungicide of choice. However, if you have some disease showing, there are products that can give you more time and flexibility in digging than chlorothalonil. There is curative action with some products. If you feel like things are getting away from you (I would be worried at 10% incidence), one more application could make a big difference and give you greater flexibility in letting the crop reach maturity. Fungicide selection is important.

Prohexadione calcium

Being able to track rows and minimize pod shed are two contributions prohexadione calcium brings to the table. It is too late to apply this plant growth regulator at this point in the season. However, if you experience more pod shed due to digging and vine inversion than you would like to see, consider one or two applications for the 2025 peanut crop. Notice that I have been saying “digging pods and inverting vines.” Prohexadione calcium can reduce pod loss in soil at the blade level. But we also know that it can help reduce pod loss as plants go through the inversion step. Less plant material going through the inverter can decrease pod loss.

Pod maturity

Okay, we talk about this all the time and encourage you to use the pod blasting approach (looking at the mesocarp color) to decide when to dig pods and invert vines. This is an important tool in your decision-making process. It can help you dig when peanuts are at optimum maturity, and it can help you get the order of fields in place from the most mature to the least mature. We gain about 1% in yield on the early side of optimum maturity for each day peanuts stay in the ground. Once we get to optimum maturity, yield plateaus for a couple of weeks before we see a rapid decrease in yield.

Digging before or after a hurricane or major tropical weather

We surveyed farmers a few years ago and asked whether or not you would dig before or after a storm. I’ve seen it work out best both ways. That was the gist of the survey results. I often say, if you can tell me whether or not there is going to be a second storm, I can give you a better answer. But in real time we are doing the best we can no matter which way we go.

Setting up equipment

Setting up the digger and inverter to match the field, vines, and weather is important. We all know that. I think we just get in a rush sometimes and accept “good enough.” While there might be an incentive to increase your ground speed by a half-a-mile per hour, we have less pod loss during digging and inverting at slower ground speeds.

Freeze damage

I’m changing my recommendation on the time between digging and a frost/freeze from 72 hours to at least 96 hours with good drying conditions.