Rice Stink Bug is not normally considered a pest of wheat, especially in the Missouri Bootheel. You can imagine my surprise yesterday (29 April 2011) when I found large numbers in a Pemiscot County wheat field and later fielded a phone call about Rice Stink Bugs in wheat from Cape Girardeau County.
Today Kelly and I went to revisit the Pemiscot County field to get a better idea of what was going on. Audra Cross (= Audra Miller before marriage) also was part of this field visit to collect ~500 of these insects as part of her Master’s thesis work investigating pesticide resistance in stink bugs (http://www.jove.com/details.php?id=2129 ). Many of the stink bugs we found were mating, but we did not find eggs or nymphs.
An economic threshold from Angus Catchot ( http://www.mississippi-crops.com/2011/04/13/high-numbers-of-stink-bugs-showing-up-in-some-mississippi-wheat-fields/ ) is one stink bug per 5-10 heads. Wheat is not as susceptible to injury as rice, so there can be a lot of them before you pull the trigger. Scott Stewart (http://www.utcrops.com/news/2011/04/stink-bugs-in-wheat-and-seedling-corn/#more-910) in Tennessee and Gus Lorenz (http://www.arkansas-crops.com/2011/04/15/rice-and-brown-stink-bugs-in-wheat-what%E2%80%99s-up-with-that/ ) in Arkansas have also seen Rice Stink Bugs in wheat this year. The critical stages are the milk and soft dough stages of wheat, so be sure to scout during this time frame. Rogers Leonard and Steve Harrison warn that treating stink bugs in wheat can flare armyworms (http://agfax.com/Content/stink-bug-treatment-wheat-louisiana-04152011.aspx ), so be sure to scout afterward if you do decide to spray an insecticide for stink bugs.
The field we visited appears to be under threshold currently, but this can change. So we will keep our eyes on this field as it moves through the critical stages.