Corn earworm update—slow to develop but some surviving the pyrethroid vial test

The corn earworm population is very slow to develop this year.  We are only getting a couple of moths each night in our black light trap here at TAREC and our pheromone trap catches are way down compared to this time last year.

Sean Malone will be posting the results of our annual corn earworm field corn survey later this week.  Those results, the percent of ears damaged by corn earworm, give us the best indication of what to expect in the coming weeks.  Worms feed in corn, drop the ground to pupate in soil chambers, then adults (moths) emerge to fly to other hosts like soybean, cotton and peanut fields.  So the size of the population in field corn is our first indicator of what the season may bring.

As in past years, we are also subjecting moths to the AVT (Adult Vial Test) with a pyrethroid insecticide. With the low population, mentioned above, we have not tested a lot of moths but the survivorship numbers are high 13-46 percent.  I cannot forecast if this will increase as the season progresses, as it has in the past, but starting at this level is significant.  Given these early results, regardless of the crop growers should be prepared to use some non-pyrethroid product ‘designed’ to target difficult to control corn earworms. These can be used alone, or tankmixed with a pyrethroid if other pests like stink bugs or kudzu bugs need to be controlled.

line graph showing CEW AVT results