Pigeon Tremex

Pest Description

• female wasps: 1 1/2 – 2 inches; yellow and black; thick bodied; 1/2 inch ovipositor (egg-laying “stinger”)
• males: lack ovipositor
• larvae: white grubs up to 2 inches; weak, fleshy thoracic legs

Host Plants, Diet & Damage

• highly stressed or recently killed maple, ash, elm, oak, hickory, sycamore, beech, apple and pear
• create round tunnels within the wood
• may increase wind, ice or snow breakage by reducing wood strength
• associated with a white rot fungus that can weaken trees
• adult wasps leave a round exit hole when emerging
• large size and strange appearance often prompts interest

Biology, Life Cycle & Damaging Life Stage

• overwinter as larvae in the heartwood
• pupate in mid- to late-summer in cells just below bark
• adults emerge in late summer and probe trees with their ovipositor
• eggs are laid directly into wood at about 1/2 inch depth
• white rot fungus softens wood that larvae will consume
• larvae feed under the bark until the following summer
• one generation per year is typical
• larvae are the damaging stage

IPM Recommendations

• Manage trees to improve or maintain health.
• Pesticide applications are not recommended because the wasp attacks dying and dead trees.