Mixing in-Furrow Products

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Comments on compatibility of in-furrow products from 2015 Peanut Information.

If someone asks about mixing materials and applying them in the seed furrow at planting, keep in mind that less is generally better in this case, especially if there is no research information on how things mix. One concern is peanut stand. That is a legitimate concern because of the expense of peanut seed. Also, in new ground, a negative impact on inoculant can be a huge issue. Applying enough nitrogen to correct an inoculant failure takes a lot of fun out of growing peanuts. Please encourage people to be careful when they mix products at any time but most especially in the seed furrow at planting.

In-Furrow Products

When considering applying products in the seed furrow at planting, keep in mind that seed cost is the highest single investment, replanting is very expensive, the planting date window is very narrow in North Carolina, and spotty or low plant populations are more prone to having tomato spotted wilt. Typically, seed is pretreated with fungicide, and there are no reports of interactions with other agrochemicals with respect to fungicide seed treatments. Recently, Cruiser Maxx received registration in peanuts as a seed treatment for thrips suppression. There are currently no indications that peanut treated with Cruiser Maxx will be more or less prone to adverse interactions with in-furrow products or pesticides applied early in the growing season.

Many growers are applying inoculant in the seed furrow as a spray or granular material. It is important to keep in mind that inoculants contain Bradyrhizobia, a living bacteria that infects peanut roots and is responsible for biological nitrogen fixation.

It is important to treat inoculants properly to ensure that bacteria are alive and able to function adequately. The in-furrow insecticides currently used in peanut to control thrips—including Orthene, Admire Pro, and Thimet as well as the seed treatment Cruiser Maxx—are compatible with inoculants. Temik, a traditional standard across the peanut belt, also is compatible with inoculant. The database on compatibility of Admire Pro and Cruiser Maxx is much more limited than data for Thimet or Orthene, but currently it appears that these products will not adversely affect inoculant performance to a great extent.

In recent years companies have pursued labels for fungicides generally used later in the season for in-furrow application. For example, Folicur was labeled but often resulted in delayed peanut emergence; however, this did not negatively affect inoculant performance. More recently, Proline has been used to suppress CBR and improve stem rot control. Currently, Proline appears to be compatible with in-furrow inoculants and insecticides.

Several distributors have in-furrow products that serve as growth stimulants and enhancers, and some growers have used these products and feel that they affect peanuts positively. From a research standpoint, it is impossible to compare all products available on the market. While growth stimulants and enhancers may in some instances affect peanuts positively, in general these products will not improve emergence or early-season growth all of the time. In fact, they probably affect peanuts—both positively and negatively—only on occasion and under conditions that are unique and hard to repeat. Given the expense of peanut seed and the fact that many growers are already applying inoculant and insecticide (and in some cases fungicide) in the seed furrow, our general recommendation is to think carefully about the possible benefits and detriments of adding unproven products in the seed furrow.

Some growers apply relatively low rates of fertilizer either in the seed furrow or to the side and below the seed furrow. Generally, research has shown little benefit from startup fertilizers for peanuts. Corn certainly responds to these applications, especially phosphorus in some cases, but peanuts seldom respond to fertilizers at planting. In some instances growers have lost stands or had peanut stands decrease considerably due to fertilizers applied in the seed furrow. With the expense of seed, our recommendation is not to apply fertilizer in the seed furrow or as a band close to the seed furrow.
Article first appeared as North Carolina Peanut Note (PNNC-2015-029)