We have initiated our annual program to assess adult corn earworms (moths) for susceptibility to pyrethroid insecticides. As you may recall, this process has been in place for many years throughout much of the southeast. Adult corn earworms (moths) are captured live and placed individually into small glass vials pretreated with either a pyrethroid insecticide, or untreated as a ‘control’. After 24 hours, vials are inspected to determine the number of dead (susceptible) and alive (resistant) moths. Each year we capture and test as many corn earworm moths as we can manage to track the percent that survive. This survival percentage is at least an indicator of how susceptible corn earworms are to applications of the many pyrethroid insecticide options for growers.
We are already seeing some alarming results. First, our moth captures are very high for this early in the season. As of this week (May 23-27), we have already captured and tested over 200 moths, many more than last year at this time. The largest sample was tested mid week and 25% survived. This is a very high early season survival rate compared with previous years and is not a good way to start the season. We will press to capture and test as many corn earworm moths as we can over the next several weeks. Stay tuned to this VA Ag Pest Advisory for weekly updates.