Peanut Pointers

Jason Woodward, Texas Agri-Life Extension Plant Pathologist

With the 2014 growing season upon us, peanut producers in the Southwest remain optimistic even though the continuing drought conditions experienced throughout much of the winter is enough to test anyone. By now, decisions on which peanut market types and cultivars to plant have been made; however, there are a few considerations when placing different market types and cultivars in a field. For example, shorter season market types, such as Spanish or Valencia are better suited for fields with marginal irrigation capacity. The indeterminate fruiting habit of peanut results in the pods reaching maturity at varying times; however, the aforementioned types generally mature 10 to 21 days earlier than runner types. The later maturity of runners or Virginias requires more irrigation. These market types may also incur more damage from diseases caused by soilborne pathogens, thus field history and the response to specific diseases are important things to consider before planting. Overall, Spanish-types are a good choice in fields with a history of severe pod rot or Sclerotinia blight. The runner cultivar Tamrun OL07 has also performed very well under these conditions. Several Virginia-type cultivars, such as AU-1101, AT- 07V and Florida Fancy, have performed very well over the past several years; however, these cultivars are thought to be more susceptible to pod rot.

David Jordan, North Carolina State University

One of the key issues growers will face is ensuring fields are free of weeds when peanuts emerge and that they are protected from thrips injury. Establishing an adequate stand of four to five plants per foot of row for Virginia market types and making sure inoculant is placed in the seed furrow appropriately are critical points. If stands are poor and the inoculant does not perform, especially on new ground, the impact on yield is essentially “uncorrectable.” While many production and pest management practices can be corrected when something negative happens, “fixing” a peanut stand or inoculation failure is almost impossible or at the least very expensive. A second batch of seed and nitrogen to correct inoculation problems on new ground take much of the profit out of growing peanuts. Soil temperature and moisture play a major role in getting a good stand and increasing the survival of bacteria in commercial inoculants. Peanuts are resilient in that they can emerge from substantial depths, so growers in rain-fed environments are encouraged to plant deep at two to three inches. This also helps ensure that bacteria in the inoculant survive hot soils in May and early June. Replanting or applying nitrogen so that peanuts can “catch up” can lead to major problems in the fall when wet soils slow operations and frost can occur. A reminder to get the crop up and going with an adequate stand and nitrogen- fixing bacteria in the right place sets the stage for success later in the season.

Glendon Harris Jr., University of Georgia Extension Agronomist

After what seemed like one of the longest, coldest winters in history in South Georgia, it is time to plant peanuts! Or is it? The longstanding University of Georgia Extension recommendation has been to wait until soil temperatures are at least 65 degrees (Fahrenheit) and holding, as in no forecast of a cold front. However, recent UGA and Auburn research studies, which were actually connected to calcium nutrition and germination, have shown that 68 degrees, rather than 65, is the more optimal temperature for optimal germination. So this means plant later right? Not necessarily. Every year is different. In South Georgia, soil temperatures should warm to the 68-degree mark somewhere around late April (let’s say April 25). But we used to recommend waiting to plant peanuts until at least May 10 or so. Why is that? Well, back when Tomato Spotted Wilt Virus (TSWV) was a critical issue in the late 90s and early 2000s, it was recommended to plant late to avoid damage and yield loss due to spotted wilt. Peanut cultivars currently being grown in Georgia have a lot better TSWV resistance so this is not as much of an issue anymore and we can go back to planting earlier. In fact, research conducted at UGA during the last three years shows that the ideal planting window is April 25 to May 10. Plus, peanuts planted in Georgia after May 15 risk reduced yields because of the lack of heat units or growing degree days at the other end of the growing season near harvest. The key is to monitor soil temperature. The four-inch depth soil temperature is better to look at than the two-inch depth since you want the roots to find warmth right after emergence to guarantee a good stand. Soil temperatures can be easily tracked using the Georgia Automated Weather Network that can be found at www.georgiaweather.net. Look for a weather station near you and happy planting!

Kris Balkom, Auburn University Agri-Program Associate

The month of April is when producers really get motivated to make preparations for planting. The first of the month is time to think about killing cover crops if they have reached a desirable size. Continuing to wait could put into jeopardy the conservation of as much soil moisture as possible, which is critically important since we never know when our last rain event will occur. Killing the cover crop by the first week also allows us to plant our peanut crop the last of April. Producers are able to plant in April once again because of the high level of TSWV resistance in the newer cultivars. Planting in April also lengthens the growing season. This helps because we have struggled the past couple of years to generate enough heat units during the normal maturity range of current cultivars. April planting does come at a price by increasing risks. Therefore, keep the seeding rate up at 6 seed per foot of row for April planting to ensure a good solid stand of peanuts. Save by reducing the seeding rate for planting later in May when soil temperatures have increased and the risk is lower.