What's eating my wasabi?

Wasabi is a moisture-loving, shade-preferring plant that is surprisingly pest-susceptible. Slugs are the primary enemy, targeting both leaves and the valuable rhizome. Aphids and crane fly larvae (leatherjackets) also cause damage. Keeping the growing environment clean and moist — without waterlogging — reduces most pressures.

Chew holes in leaves and feed on the developing rhizome; wasabi's moist, shaded growing conditions are ideal slug habitat; can destroy a crop overnight. Iron phosphate pellets; copper tape barriers around containers; hand-pick at dusk; remove dying outer leaves promptly as slugs congregate there.

Colonies on leaf undersides and new growth; honeydew and distorted leaves; transmit viruses that can stunt the slow-growing rhizome. Strong water spray to dislodge; insecticidal soap or neem oil; keep plants in good airflow to discourage build-up.

Soil-dwelling larvae chew through roots and the base of the rhizome; plants wilt and collapse at soil level with no visible above-ground pest. Nematodes (Steinernema carpocapsae) watered in during late summer; disturb soil to expose larvae to birds; avoid over-watering which increases larval survival.