European Elm Flea Weevils - Tiny Pests, Big Impact

The European elm flea weevil (Orchestes alni) is a small but troublesome insect pest that has been causing significant damage to elm trees across the United States. These tiny insects, measuring only 3 mm in length, are known for their distinctive appearance and destructive feeding habits.

Life Cycle and Behavior

Adult weevils emerge in spring, ready to wreak havoc on newly developing elm leaves. With their snout-like mouthparts and enlarged hind legs for jumping, these red-brown beetles with black markings are well-equipped for their leafy feast.

After mating, females lay eggs in the mid-veins of fresh leaves. The resulting cream-colored, legless larvae tunnel through the leaf tissue, creating serpentine mines that expand as they grow. This larval feeding is the first wave of damage inflicted on the trees.

                               European elm flea weevil adult. | Whitney Cranshaw, Colorado State Univ., Bugwood.org

Damage and Impact

The weevils' assault on elm trees is twofold:

1. Larval mining: Creates winding patterns within leaves
2. Adult feeding: Produces small holes on leaf undersides

While this damage rarely kills the tree, it can significantly mar its aesthetic appeal.
Siberian elms and certain Asian elm hybrids are particularly susceptible to elm flea weevil.

Larva of European elm flea weevil on left and elm leafminer on right. | Whitney Cranshaw, Colorado State Univ., Bugwood.org

Management Strategies

Maintaining plant health through proper tree care practices is crucial. In southeast Michigan, a preventative soil drench application should be applied around mid-April; or a trunk-injected insecticide can be done in early to mid-May.

As elm flea weevils continue to spread across North America, vigilance and proactive management will be key to protecting our landscape elm trees from these tiny but persistent invaders.

To have your elm trees inspected for this, or other harmful disease or insect pests, contact Owen Tree & Lawn Care at 800-724-6680.