After weeks of successive trap catches being empty or in the single digits, we have seen a dramatic increase in the last couple of days in the number of corn earworm moths captured in our pheromone traps throughout the state. At multiple locations catches jumped from near nothing to hundreds of individuals in a single night. This is likely related to a combination of factors including the maturation of the second generation of the pest and the progress of field corn, with most of it passing out of the silking stage. This creates high pressure to any of the remaining sweet corn on the landscape that is at or nearing the silking stage. Now is the time to be diligent with your spray program, monitoring crop progress and making applications (preferably with drop nozzles) at regular intervals to align with product recommendations and crop growth. The weather in most regions is favorable for corn growth resulting in a need for frequent applications to protect the developing silk. Be sure to check the CEW trapping website for updates daily. The current action threshold, now that field corn is done silking, is 1 moth in the trap per night. Spray decisions should be made based on the closest trap location. In the table online, if no value is entered the trap was not emptied. A zero will be present in the data table if the trap was checked and there were no moths present. Read the label of any product carefully to determine when to apply the product (% of crop silking) and what the recommended application intervals are; both of these factors are highly dependent on product selection. Remain diligent and you are looking to have a great late-season crop!
Figure 1. Adult CEW recovered in a trap.
Figure 2. CEW larvae in developing ear of corn.