As we approach bloom, Sparganothis fruitworm, spotted fireworm, and blackheaded fireworm adults will start to emerge. Growers need to start monitoring for Sparganothis adults using pheromone traps. As in previous years, I will be tracking the activity of Sparganothis adults using a degree-day model we developed in collaboration with Dr. Shawn Steffan from University of Wisconsin-Madison/USDA-ARS. Based on our degree-day model for Sparganothis, flight initiation is expected at around 596 DD (using March 1 as biofix; see chart). As of June 01, Sparganothis has accumulated 345 DD (using April 15 as biofix). Last year, at around this time, Sparganothis had already accumulated 529 DD. This means we are about one week behind from last year. This indicates that flight activity has not started and will not start until about 10-11 days from now. Growers are advised to place pheromone traps for monitoring this pest by the end of this week or, at the latest, by early next week.
Sparganothis fruitworm degree-day model
