Every year about this time, soybean producers begin deliberating the justification for making “yield enhancement” applications that may include one or more fungicides and insecticides as needed. The scenario changes every year, and growers need to base the selection of products on recent scouting of fields for diseases and insects.

Having spent almost two decades as a crop consultant prior to joining Extension, and more than that since, I have found it difficult to make what some people call “automatic” applications of pesticides to crops, but when it comes to the yield enhancement application for soybeans I have accepted that the justification is almost always there.

A careful study, however, of the specific field situation is needed before making the decision on products to be included.

The basic component of the yield enhancement application is the fungicide package. For a long time this consisted of a strobilurin product since trials done during the years of the SMART program showed good yield responses to this class of fungicide.

This is still true, but with a more complex set of disease challenges such as strobilurin-resistant frogeye and the threat of Asian rust the program may need modification in some cases to include a triazole products in order to broaden the spectrum of fungi that may be managed by the application.

New products have also been added to the list of effective materials.

Rate is another issue, with some growers cutting the rate of the strobilurin material from the recommended 6 ounces to a more economical 3 ounce rate. In situations where disease is not apparent, the rate may be reduced somewhat, but it probably should not be reduced by half as in this case, but by a more prudent third.

And in fields where frogeye is suspected of being tolerant to strobilurin products, a second material such as TopGuard may be combined with the strobilurin for improved effectiveness.