What's eating my zantedeschia jucunda?

Zantedeschia jucunda, a South African calla relative grown outdoors in borders or pots, is most troubled by aphids and slugs. Sap-sucking aphids distort new growth; slugs rasp holes in the broad leaves overnight. Thrips can scar flower spathes, and vine weevil grubs occasionally attack rhizomes in containers. Good drainage and garden hygiene are your first defence.

Clusters of soft insects on new shoots and undersides of leaves; sticky honeydew and distorted growth. Blast off with a strong water jet; apply insecticidal soap or neem oil spray. Encourage ladybirds and lacewings.

Irregular ragged holes in leaves, especially overnight; silvery slime trails left on foliage and soil. Apply ferric phosphate pellets around plants; use copper tape on pots; hand-pick at dusk. Avoid over-watering.

Silver-streaked or flecked scarring on leaves and spathes; tiny dark frass dots visible under magnification. Remove and dispose of heavily affected leaves; spray with spinosad or insecticidal soap; use sticky yellow traps.

Notched leaf margins from adult beetles (night); sudden plant collapse when grubs eat rhizomes underground. Apply nematode drench (Steinernema kraussei) in late summer; use sticky barriers on pot rims; inspect rhizomes at lifting time.