What's eating my astilbe 'fanal'?

Astilbe 'Fanal' is largely pest-resistant, but black vine weevil is its most consistent threat — larvae destroy roots underground while adults notch leaf margins at night. Asiatic garden beetle adults also feed on the foliage in midsummer. Aphids and spider mites may appear during hot, dry spells.

Adults notch irregular bites from leaf edges; C-shaped larvae devour fine roots and bore into larger roots, weakening or killing the plant. Apply pathogenic nematodes (Heterorhabditis bacteriophora or Steinernema kraussei) to moist soil in late summer; imidacloprid soil drench early season provides systemic control.

Reddish-brown adults emerge in late June–July and skeletonize astilbe foliage; larvae (white grubs) feed on roots in the soil. Hand-pick adults at night; apply beneficial nematodes or milky spore to soil to target grubs; use pyrethrin spray on foliage if adults are numerous.

Clusters on young stems and flower buds cause distorted growth and sticky honeydew; mainly a problem in spring and early summer. Knock off with a firm water spray; apply insecticidal soap or neem oil; beneficial insects (ladybirds, hoverflies) usually keep populations in check.