Results from the generation-one trials suggest that the decision to use a fungicide and/or insecticide seed treatment is not a simple yes/no answer. Across the 27 location-years where we tested these products, the relative yield ranged from -6.4% to +11.6% across environments. The relative yield ranged from -3.2 to +7.7% across the seven varieties that were also examined over the course of the study.

Specifically examining the two seed treatments indicated that the probability of at least a breakeven response to the seed treatment was driven by both cost of seed treatment and yield environment. For example, at $6/bu. soybeans and a 40-bu./acre yield environment, the probability that the use of a seed treatment covered the cost the of the application was 42% for ApronMaxx and 3% from CruiserMaxx. As both yield potential and soybean commodity price increased, the probability of covering cost also increased to well over 50%.

How does this translate back to yield though? Across the different relative yield ratios and cost-price structures, the actual increase in yield ranged from 0.6 bu./acre to 2.3 bu./acre. Our original analyses that did not factor the cost-price structures but just focused on yield response were very similar with what we found factoring in the cost-price structures.

How can such information be used? Our experience has been that when spring conditions are cool and wet and when planting date is in late April to early May, the use of seed treatment fungicides are an effective tool, especially given the current value of seed. Additionally, the probabilities we quantified in our generation one trial provide a framework for the grower to improve their understanding of how often they might expect a response over time thus enabling questions such as: (1) holding my seeding rate constant, what does the additional cost per unit for seed that is treated require in terms of yield to maximize the return on investment, and (2) given the increase in cost per unit for seed, can I consider reducing my seeding rate without affecting yield? Lastly growers can use this table to impose their own level of risk to determine the value of a seed a treatment to their own operation.