Evaluation of a grower-friendly attract-and-kill strategy for apple maggot control in New England apple orchards

Most of the apple maggot fly, Rhagoletis pomonella (Walsh) (Diptera; Tephritidae) injury in commercial apple orchards in New England originate from flies immigrating from unmanaged hosts. An attract-and-kill strategy can intercept immigrant AMF before they penetrate into the block interior. This study evaluated the efficiency of attract-and-kill strategy involving the use of attractive lures and insecticide sprays in combination with sugar added as phagostimulants, applied to perimeter-row trees. The experiment was conducted in 6 and 11 commercial Apple Orchards in 2019 and 2020 respectively. Two treatments were compared: (1) attract-and-kill and (2) grower control. The attract-and-kill block involved the use of lures deployed on the perimeter of the block plus red spheres as a monitoring tool. In these blocks, perimeter-row trees were sprayed with insecticide mixed with 3% sugar added to the tank mix. In the grower control blocks, two or three insecticides were applied to the entire block by the grower. Unbaited red spheres deployed in the block interiors were used to monitor the level of AMF penetration by weekly recording data until harvest. At harvest, fruits were sampled from the interior and perimeter of the two treatments to record AMF injury. Red sticky spheres on perimeter-row trees in association with synthetic AMF lures in attract-and-kill blocks captured substantially more (9-60 times) wild AMF than interior unbaited spheres in the control blocks, indicating that an attract-and-kill approach plus synthetic lures on perimeter-row trees in association with perimeter-row sprays of insecticides containing 3% sugar were effective.