Your corn should be in some stage of planted, emerged, or to six-leaf stage or taller by now. That means it's time to scout for pests, no matter what the stage is. Relying on seed treatment insecticides and GMO corn to do all the work may be optimistic this spring.
For example, armyworm is prevalent in the South and moving into Midwestern parts of the Corn Belt. Purdue University Extension entomologists say larvae attack quickly, can do great damage in certain fields, are most likely to be found in no-till cover crop fields and aren't affected by seed treatment insecticides.
GMO hybrids may affect them, but they eat so fast they may do considerable damage before the protein backs them off.
Related: Armyworms Marching Through Missouri
Corn rootworm larvae should be hatching soon. Tom Turpin, Purdue entomologist, determined that the first hatch usually lines up with arrival of fireflies at night. None have been reported yet. The season continues to run about two weeks behind.
Just because you have GMO corn doesn't mean you have rootworm protection. There is still corn borer and Roundup Ready corn sold without below ground protection. Make sure you know what your tags said and whether you have protection or not.
If not, you may want to scout once you hear hatch has begun. You're looking for tiny, white larva.
Wireworms and other pests that occur in patches should head deep underground and no longer be a problem once temperatures heat up and stay there. Until then they have the possibility to chew through seedlings.
Black cutworm moth counts were extremely high in some part of the Corn Belt this year. Even if you think you're protected by insecticide or GMO traits, you might want to scout. Cutworm damage takes out plants and stands, usually in patches within a field. Corrective action is possible if you can act before the larvae have done too much damage.