1a.Objectives (from AD-416):
Objective 1: Investigate novel interception strategies by deploying attractant-baited traps as a threshold between commercial nurseries and the overwintering woodlots of Xylosandrus crassiusculus and X. germanus.
Objective 2: Optimize trapping as a monitoring and mass trapping tool for ambrosia beetles.
Objective 3: Develop a push/pull strategy for ambrosia beetle pest management by screening repellents and attractants.
1b.Approach (from AD-416):
Exotic ambrosia beetles belonging to the subfamily Scolytinae are increasingly being recognized as key pests of field-grown nursery crops. The granulate ambrosia beetle, Xylosandrus crassiusculus, has become a significant pest of ornamental nursery crops stock since accidentally being introduced into the U.S. from Asia. Studies aimed at improving monitoring and detection techniques are necessary for predicting attacks and closely timing insecticide applications with the flight activity of X. crassiusculus. Experiments on repellents and attractants could also be used to develop a “push-pull” management strategy, whereby ambrosia beetles are “pushed” or repelled away from vulnerable nursery stock and “pulled” or attracted into destructive traps. The objectives of this proposal are to investigate novel interception strategies for X. crassiusculus, to optimize trapping as a monitoring and mass trapping tactic, and to develop a push/pull strategy for use in the nursery agroecosystem. Traps will be deployed to test potential volatile attractants for X. crassiusculus, which will be correlated with environmental data. Trap trees will also be developed for testing repellents, reduced-risk insecticides, and mass trapping purposes.
The cooperator conducted research into improved detection and management strategies for ambrosia beetles attacking ornamental nursery stock. Collaborative research was conducted with ARS scientists into: (1) developing a trap tree strategy for detecting and trapping ambrosia beetles, (2) determining the influence of water stress on tree attractiveness and susceptibility to ambrosia beetles, and (3) screening repellents against ambrosia beetles. Experiments indicated that deploying ethanol-injected trees and bolts is a promising strategy for intercepting ambrosia beetle immigrating into nurseries and deflecting ambrosia beetle attacks from valuable nursery stock. The antiaggregation pheromone verbenone was also screened for repelling ambrosia beetles, which could be used in conjunction with the attractive traps as part of a push-pull system. The influence of water-stress (flood and drought) on the attractiveness and susceptibility of ornamental trees to ambrosia beetles supported our collaborative projects that physiologically-stressed trees are specifically targeted for colonization. Tissue samples sent to ARS also confirmed that water-stress induced the production of ethanol by trees.
This research relates to the following objectives of the parent project: (1) to reduce, through knowledge generated by research, crop losses and damage caused by insect pests of ornamental nursery crops, turf, and other horticultural crops; (2) to develop alternative management strategies for pest control that will reduce dependence upon traditional uses of insecticides, and lessen impact on groundwater.