What's eating my primula japonica?

Primula japonica (Japanese primrose) is a robust candelabra primula for moist, shaded borders. Vine weevil grubs are the most damaging pest, destroying roots and causing plant death. Aphids and vine weevil adults attack above ground, slugs and snails graze lush foliage overnight, and red spider mite can infest plants during dry warm spells.

White grubs eat roots causing wilting and collapse; adults leave characteristic C-shaped notches in leaf margins. Apply nematode drench (Steinernema kraussei) to moist soil in late summer; inspect crowns of purchased plants.

Colonies on flower stems and leaf undersides cause distortion, yellowing, and honeydew deposits. Knock off with water; apply insecticidal soap or neem oil; encourage natural predators.

Rasp large holes in the soft leaves and chew through flower stalks, especially in spring. Hand-pick at dusk; set beer traps; apply iron-phosphate pellets around each clump.

Fine webbing on leaf undersides; stippled, bronzed foliage if plants dry out during warm spells. Mist foliage regularly to raise humidity; apply predatory mites (Phytoseiulus persimilis) as bio-control.