What's eating my common spike-rush?

Common Spike-rush is a tough wetland sedge with few serious pest problems. Aquatic moth larvae occasionally bore into stems; snails and pond-dwelling invertebrates may graze young tips. Waterfowl graze the basal shoots. The plant's main ecological value is as insect habitat — emergent stems are used by dragonfly and damselfly nymphs climbing out of the water.

Bore into stems causing individual shoot collapse and brown wilting; most noticeable in late summer; rarely affects overall plant density Remove collapsed stems to reduce carry-over; Bt spray on young emergent growth; large established mats outgrow low-level damage without intervention

Grazing on stem tips and new growth, particularly on plants in shallower water or pond margins; more visible on smaller, younger plantings Introduce predatory fish that control snail populations; manually remove large snail aggregations; no pond-safe molluscicide appropriate in this habitat

Basal shoots and rhizome tips grazed; uprooting of shallow plantings in early spring when other food is scarce Wire mesh or netting protection on newly planted areas; establish in water 15-30 cm (6-12 in) deep; once dense mats form, waterfowl grazing rarely causes lasting harm