SHOTHOLE BORER

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Title: SHOTHOLE BORER
Description: LATIN NAME: Scolytus rugulosus (Ratzeburg) LIFE CYCLE: Overwinter as mature larvae or pupae in host. Adults emerge in May and tunnel under bark to lay eggs. Larvae present April to July; second adult generation appears August to September to produce overwintering larval generation. Two generations per year. MONITORING: Glass barriers with a base filled with soapy water can be suspended in orchards to monitor adults. Check branches for entry holes near buds. HOSTS: Native and cultivated trees. COMMENTS: The presence of small holes at the base of buds and sometimes strings of clear gum or resin exuding from entry holes is characteristic of shothole borer attacks. Larvae feeding on the cambium will create a network of tunnels under the bark. This contrasts to ambrosia beetles that tunnel into the heartwood and cause some discoloration of the cambium and heartwood. BODY LENGTH: Adult - 2.0 mm; Mature larva - 3.0 mm.