Ministry of Agriculture
Xyloborus dispar (Fabricius)
Ambrosia beetle beside tunnel excavated through heartwood of apple branch
Entry holes (note sawdust) of female ambrosia beetles tunneling into apple tree
Life Cycle: Overwinter as adults in host. Adults appear in April and after mating, tunnel into a host to lay eggs. Larvae are present May-July. New adults remain in host to overwinter. One generation per year.
Monitoring: Tanglefoot or some other sticky material applied to the trunks may trap adults and indicate their presence. Ethanol-baited Lindgren Funnel Traps can also be used to detect adults. Look for small exit or entry holes (2mm).
Hosts: Native and cultivated trees.
Comments: Ambrosia beetles tunnel into heartwood causing brown strips of dead tissue in the cambium and discoloration in the heartwood. This contrasts to shothole borers that feed on the cambium, leaving a network of tunnels under the bark.
Body length: Adult - 3.0mm; Mature larva - 4.0mm