Asparagus beetle

Asparagus beetles appear as small, metallic blue-black insects with cream-colored spots, feeding on emerging spears and fern foliage from mid-spring onward. You will see chewing damage on spear tips and dark, shiny eggs standing upright on spears. Both adults and gray, slug-like larvae feed throughout the growing season, reducing fern health and next year's harvest potential in Western Washington gardens.

Harvest spears promptly to remove eggs before they hatch. Hand-pick adults and larvae from ferns in morning when they are sluggish. Remove old fern debris in fall where adults overwinter. A tiny parasitic wasp attacks the eggs naturally. Neem oil or spinosad provides targeted control for heavy infestations without broad-spectrum damage to beneficial insects.