The short answer to whether you should or should not spray is no for 99 percent of our corn growers. 

Stink bug abundances in wheat are even lower than last year. Furthermore, most corn is nowhere near the most “stink bug susceptible” stage (just prior to tasseling). 

Most problems with stink bugs in corn come from brown stink bugs moving from wheat into adjacent corn fields days following harvest.

Wheat harvest is beginning and should be in full swing soon. Therefore, my prediction is that there will be fewer problems with stink bugs in corn than we’ve seen in the past.

For a deeper treatment of the subject read on.

Before I talk about corn, I want to point out that you probably won’t want to spray stink bugs in your wheat. Pyrethroid labels carry a 30-day pre-harvest interval restriction for use in wheat. So if you sprayed your wheat now, you couldn’t harvest until July. 

Additionally, stink bug densities must be extremely high to cause a yield loss in wheat. I have swept a lot of wheat fields for stink bugs and have never seen yield reducing densities.

Right now, our only effective option for stink bug management in corn is to use ground-applied sprays

Foremost, you should only treat for stink bugs if you reach threshold levels (listed here). These thresholds are based on experimental data and are already conservative. I have a high degree of confidence in them, as a result. 

Until V6, the economic threshold is four stink bugs per plant. The most susceptible time for stink bug injury in corn is when the ear is forming, during ear elongation, and during pollen shed. Treat at one stink bug per four plants during these stages.