Willow Flea Weevil: Appearance, Territory, Damage and Life Cycle

Latin Name: Rhynchaenus Rufipes

Appearance: Adults are small, elliptical black weevils (0.1 inch long) with orange legs that devour tiny circular holes in the leaves, generally from the underside, leaving only the opposite leaf-surface over the hole. Adults initially appear in mid-May, when new leaves emerge. Holes are still being dug into the ground in July.

Hosts Plants: The willow flea weevil appears to favor bayleaf (laurelleaf) willow, Salix pentandra, although it will attack other willows, Lombardy poplar, and aspens as well. The willow flea weevil is often not a concern on weeping willow, unless it is cultivated in close proximity to bayleaf willow. The area is frequently infected with Salix alba.

Territory: Eastern Canada and Some areas of US

Damage Insect Cause: These little insects can cause significant browning of willow (and poplar) leaves beginning in mid-summer. The leaves may keep their original form and remain on the trees, although browned leaves frequently fall in abundance in late August and September. Depending on the intensity of the damage, the natural green hue of the leaves takes on a bronze or brownish tint beginning in July and growing more noticeable through August.

Life History and Habits: In early June, eggs are deposited in tiny clumps on the leaves. Larvae (grubs) hatch quickly, eat in rows, and take just the leaf surface, leaving a skeleton of leaf veins. Scalarized leaves turn brown. Larvae are jet black and small at first, but grow to be 1/4 inch long when fully mature. There is more than one generation. Winter hibernation occurs in the same locations as for weevils.