Brown stink bug grownup exhibiting straw-like mouth piercing a grass stem. (Picture Credit score: John Obermeyer / Purdue Extension)
Stories from these checking cornfields point out that brown stink bugs had been busy earlier feeding on seedlings and at present inside whorls. Broken crops, stunted and/or leaves with holes and yellow striping, are fairly apparent throughout the whorl stage. The stink bug issues are worse in heavy-residue fields the place corn was planted into soils not appropriate for good seed-slot closure.
Stink bugs feed on corn by inserting their straw-like beak into the stalk or whorled-leaves whereas injecting an enzyme, which helps digest plant tissue. They like to feed on new progress. When seed slots should not correctly closed throughout planting, stink bugs typically feed on, or close to, the rising level.
It is very important do not forget that seedling corn crops are most susceptible to assault and injury. By the point apparent feeding signs seem, the injury has been performed. Signs fluctuate, starting from linear holes with a yellowish edge within the leaves, twisted or deformed stalks, plant suckering, and infrequently plant loss of life. The injury can typically be confused with different causes, e.g., herbicide damage, mechanical injury, and many others. Brown stink bugs might at present be seen within the corn whorls, however their feeding injury on leaves within the whorl is of little concern.
How Stink Bugs Trigger Whorl Harm in Corn
Sampling for stink bugs at corn emergence is troublesome and time-consuming, as one should crawl on the bottom and examine on the stalk/soil interface. Their early injury just isn’t noticeable for weeks, too late to guard the gnarled corn. Stink bugs feeding within the whorls may be handled, however doing so is just revenge, because the ugly leaf injury has not been attributed to yield loss.
Well timed planting, with ideally suited soil situations, was a problem this spring, particularly these with heavy residues/covers. The quantity of stink bug injury being discovered now’s a reminder of these moist situations a pair months in the past. Blissful scouting!
Written by John Obermeyer, Built-in Pest Administration Specialist with Purdue Extension.