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Poplar and Willow Borer – Cryptorhynchus lapathe

Poplar and Willow Borer (Cryptorhynchus lapathe) Latin Name: Cryptorhynchus lapathe Common Name: Poplar and Willow Borer Appearance:
  • Male and female adults are rough-surfaced, snout-nosed beetles 8 to 10 mm long. Except for the back third of their stiffened wings (elytra), which are originally gray-pink but eventually turn light brown, they are mainly black. Before mating, adults consume a large number of young succulent shoots.
  • Females develop little punctures in the shoots and deposit a single egg (possibly as many as three) in each puncture over the summer.
  • The larvae eat once the eggs hatch by mining the bark and then moving into the wood.
  • Larvae are creamy-white, C-shaped grubs and have a full-grown length of 13 mm.
Host plants: The entire poplar and willow borer except poplar tremuloides are considered as host plants. Territory: Quebec, Newfoundland, Ontario, British Columbia Damage caused by Poplar and Willow Borer: Many wood-boring insects are typically found in live hardwoods. The carpenterworm (Prionoxystus robiniae [Peck] and the cottonwood crown borer are the most prominent (Sesia tibialis [Harr.]). When a tree is attacked by one or more of these borer species, it is generally structurally weakened and vulnerable to wind and snow damage. Life history and Habits: In the Prairie Provinces, the poplar-and-willow borer takes two years to complete its life cycle, and the adult borer can survive a third winter. Adults emerge during spring after overwintering in the wood, and the female deposits eggs in the stem in slits bitten into the bark shortly after. Young larvae burrow into the cambium around the stem, but they tunnel into the wood as they mature. They pupate in expanded galleries in the stem when completely mature. Some pupae develop into adults and emerge in the fall to lay additional eggs, while others overwinter and emerge as adults in the spring.