What's eating my begonia scharffii?

Begonia scharffii (elephant ear begonia) is a large shrub-type houseplant. Its thick, hairy leaves and soft stems attract mealybugs at stem joints, and thrips that rasp the large leaf surfaces. Spider mites can colonise the undersides in dry centrally-heated rooms. Mealybugs are the primary threat given its bushy, densely-branched habit.

Waxy white clusters in hairy stem axils; honeydew drops onto lower leaves; growth slows and leaves yellow Swab joints with isopropyl alcohol; spray with insecticidal soap or neem oil, parting stems to reach all surfaces; repeat every seven days

Silvery scarring across large leaf surfaces; distorted emerging leaves; frass visible on undersides Apply spinosad insecticide; introduce Amblyseius cucumeris predatory mites; use blue sticky traps; remove and dispose of heavily affected leaves

Speckled yellowing on leaf surface; webbing on hairy undersides; plant loses vigour in heated indoor environments Boost humidity around the plant; rinse foliage; apply neem oil spray to undersides; introduce Phytoseiulus persimilis for established colonies