Cranberries have started to bloom, and bees are active in bogs. If insects have been effectively managed prior to bloom, we recommend no sprays at this time. A reminder: when bees are present, your choices of insecticides are insect growth regulators (IGRs) such as Intrepid 2F or Bt products such as DiPel.
During bloom, we recommend monitoring insect populations using pheromone traps. Pheromone traps should be used particularly to monitor the activity of Sparganothis fruitworm and blackheaded fireworm, two key pests in New Jersey.
Degree-Day Model for Sparganothis Fruitworm
Sparganothis fruitworm adults
Together with Dr. James Shope, Assistant Extension Specialist in the Department of Environmental Sciences at Rutgers University, we have been working on refining a degree-day model for Sparganothis fruitworm using trapping data from New Jersey. According to this model, 25% flight activity should occur at 840 degree-days, and peak flight activity at 952 degree-days (starting on April 15). As of today, Sparganothis fruitworm has accumulated 724 degree-days, indicating that flight should have started but has not yet reached 25%. Note that this model includes data from many bogs and varieties, which may behave differently from the overall model. Therefore, it is advised to monitor closely as the expected peak flight approaches.
