With soybean commodity prices at record high prices, the number of questions regarding key management considerations also remains high. One of the questions we often receive regards the use of seed treatments, in particular the use of seed treatment fungicides and/or insecticides. Since 2008, we have conducted trials throughout Wisconsin to examine if seed treatments are economically viable for soybean production. In particular, we are most interested in trying to answer the following question: “What is the probability that if I use a seed treatment, the cost of the application is covered?”

Our research trials have been conducted under what we call generation one (2008-2010) and generation two (starting in 2011). The first-generation trials were conducted at nine locations each year, for a total of 27 location-years. Results from these trials were recently published in the journal Crop Science (Esker, P.D., and Conley, S.P. 2012. Probability of yield response and breaking even for soybean seed treatments. Crop Science 52:351-359) and have also been discussed during the past several winter Extension meeting seasons. In this article, we will focus on summarizing those results in some detail.

In our generation-one trials, two seed treatments and an untreated control were examined. They were: ApronMaxx RFC (fludioxonil + mefenoxam) and CruiserMaxx (fludioxonil + mefenoxam + thiamethoxam) (Syngenta Crop Protection, Inc., Greensboro, NC). There were four soybean varieties per location per year and the varieties did differ over years, although within a year, the same varieties were examined at all locations.

In addition to examining the effect of seed treatment and variety on yield, we were very interested in quantifying the probability of breaking even. To do this, we examined different components of cost and expected return. For example, the two seed treatments differ in the cost per unit ($4 for ApronMaxx RFC and $10 for CruiserMaxx, respectively). Also, the observed yield across trial years ranged from 35 to 85 bu./acre so it was important to examine what we might term are “low” (40 bu.), “medium” (60 bu.) and “high” (80 bu.) yield potential environments.

Lastly, it was important to examine these responses across a variety of soybean commodity prices and we started by examining $6, $9 and $12/bu. soybeans. Using the different cost-price structures, we quantified the probability of breaking even based on the percentage increase or decrease in yield with the use of a seed treatment compared to the untreated control.