Impact of stress reducer agents on ornamental trees for the management of ambrosia beetle

Ambrosia beetles are wood-boring beetles that attack stressed trees. Trees under flood stress emit ethanol, which is the primary attractant cue for the ambrosia beetle. Treating trees prior to flooding with systemic acquired resistance (SAR) activators may alleviate stress induced due to flooding; however, the study of such compounds on flooded ornamental trees is limited. Here, we aimed to evaluate the effect of stress-reducer agents, such as some fertilizers and fungicides, on ethanol emission and ambrosia beetle attack of flood trees. Treatments included: 1) Regalia bio fungicide, 2) Reliant fungicide, 3) Axiom Harpin Protein, 4) Flooded control, and 5) Unflooded control, arranged in a randomized complete block design. Thirty native dogwood plants were maintained in the pot-in-pot experimental set-up and treated with stress-reducer agents (six plants/treatment), including six plants each of flooded and unflooded control. Standing water was maintained around the base of the inner container for flooding treatment. Ambrosia beetle attacks were assessed every other day throughout the experimental period, and volatile organic compounds were collected from twig tissues to assess the ethanol emissions. The results suggest that stress-reducer agents, such as those tested in this study, can be an effective tool for reducing tree stress and management of ambrosia beetle attacks.