What's eating my begonia?

Mealybugs are the most persistent begonia pest, hiding in leaf axils and along stems. Spider mites thrive on tuberous types in dry indoor air. Vine weevil larvae destroy roots of outdoor tub-grown begonias. Thrips and aphids attack flower buds outdoors. Inspect the axils and undersides of new growth regularly — mealybugs establish quickly and are hard to eradicate once entrenched.

White cottony wax deposits in leaf axils and along stems; leaves yellow and drop; honeydew promotes black sooty mould. Dab individual bugs with isopropyl alcohol on a cotton swab; spray with insecticidal soap or neem oil. Isolate affected plants immediately to prevent spread.

Pale stippling and bronzing on leaf surfaces; fine webbing underneath; defoliation in severe outbreaks, especially in dry conditions. Raise humidity around the plant; apply neem oil or miticide spray to leaf undersides. Repeat every five to seven days for three cycles.

Adults notch leaf margins; larvae eat roots of container-grown tuberous begonias, causing sudden collapse of the plant in late summer. Apply beneficial nematodes (Steinernema kraussei) to moist compost in late summer. Repot each year and inspect roots; discard infested soil.

Silver streaking or scarring on petals and leaves; buds may fail to open or open distorted. Remove affected flowers; apply spinosad or insecticidal soap spray to buds and undersides of leaves. Blue sticky traps help monitor.