Are Fall Armyworm Infesting Corn, too?

Fall Army Worm in Late Corn

We have all experienced the massive damage that fall armyworms did on our forage crops and turf.  Keep in mind that fall armyworm can also damage corn.  We have found late-stage caterpillars feeding on corn that was planted on May 25 and on June 23rd.  The good news is that corn with above-ground Bt offers protection against fall armyworm.  The bad news is that Bt resistance has occurred in other states to our south (which is where our fall armyworms likely came from). In some of these areas, fall armyworm has shown evidence of resistance to corn with the Bt proteins Cry1Ab and Cry1F. Corn with the traits Cry1A.105/Cry1Ab2 and Vip3A remain effective against fall armyworm (see the Bt trait table: https://agrilife.org/lubbock/files/2021/02/BtTraitTable_Feb_2021B.pdf).  Although we have not seen any Bt resistance with fall armyworm in Ohio, we also don’t often see fall armyworm at all.  Now is the time to check corn ears for feeding damage.  At this point, control would be difficult since the caterpillars are protected in the ears. So why is checking Bt corn important? If and when, we have a fall armyworm invasion again, we need to make sure that these traits are holding up as we expect.  We have had a large enough issue with forage and turf—we don’t need another issue in corn.

Finally, keep in mind that most fall armyworm are pupating now which means adults will be flying soon. In fact, we have already seen some moths in traps already.  We are expanding our trap network to help us predict the likelihood of another generation that may impact forage regrowth and potentially any winter wheat or cover crops that begin to emerge.

Crop Observation and Recommendation Network

C.O.R.N. Newsletter is a summary of crop observations, related information, and appropriate recommendations for Ohio crop producers and industry. C.O.R.N. Newsletter is produced by the Ohio State University Extension Agronomy Team, state specialists at The Ohio State University and the Ohio Agricultural Research and Development Center (OARDC). C.O.R.N. Newsletter questions are directed to Extension and OARDC state specialists and associates at Ohio State.