Coinciding with the wheat harvest, brown stink bugs have been moving into pre-tassel corn in the southeastern region of our Virginia. The entomology department has scouted fields over threshold in Chesapeake and Virginia Beach. So far this season, stink bugs are present in low numbers in northern, central, and western regions of the state.
Thresholds for stink bugs in field corn are (From Dominic Reisig at NCSU):
one stink bug per four plants during ear formation, elongation, and pollen shed
one stink bug per two plants nearing the end of pollen shed to the blister stage.
Plant injury from stink bugs may include:
Holes in leaves and, in severe cases, twisted plants.
It is important to remember that this bug typically infests on edges of fields and in spotty locations. It is possible, though unlikely, that stink bugs will infest an entire field. Spray volume is critical if you decide to spray – use a high volume to ensure that sprays penetrate the canopy. Insecticides labeled for stink bugs in corn (e.g., Baythroid XL, Karate Z, Warrior II) must come into direct contact with insects to kill them.