Scout for Stink Bugs in Corn During Ear Shoot Development

While we have quite a few corn fields beginning to tassel, many more are have a little ways to go.  There is a period of about 10-14 days when ears shoots become visible or begin to bulge on the side of the stalk that is very susceptible to stink bug damage and should be scouted for closely.  Visible ear shoot development generally occurs around V15-V17, depending on hybrid.  Typically in MS we have not seen a tremendous amount of ear damage in corn in the past but it can happen, and does happen in some field every year.  Unlike early season damage where a percentage of plants fed on by stink bug recover, when ears shoots are fed on, it usually results in the loss of the ear.  The response from ear shoot feeding is generally referred to as a “cow horn ear”.  During this stage it seems fairly difficult to scout for stink bugs in head high or taller corn because stink bug numbers are generally low.  However, if present they are usually found easily.  Do not assume you will automatically have a problem but scout and look for stink bugs sitting on the side of the stalk.  Usually they can be found within a collar or two above are below the ear shoot.  Typically during this stage most stink bugs will be found in field borders.  In fact, border sprays alone can sometimes take care of the problem if numbers fall off as you move into the field.  The threshold for stink bugs during the ear shoot stage is 5% infested plants in MS.  Once ears have emerged and begin to fully elongate the threat from malformed ears due stink bugs is past.

"Cow Horn Ear" From Stink Bug Feeding During Ear Development

"Cow Horned Ears" From Stink Bug Feeding During Ear Development