What's eating my round-leaf calathea?

Calathea orbifolia's large, silver-striped round leaves are a prime target for spider mites in dry indoor environments. Scale insects can colonise the broad stems unnoticed. This species is sensitive to many pesticides, so early intervention with insecticidal soap and consistent high humidity are preferable to chemical treatments.

Fine pale stippling across the broad leaf surface; webbing on undersides when populations are high; overall dull, washed-out leaf colour. Gently wipe leaves with a damp microfibre cloth. Apply insecticidal soap spray (avoid neem oil, which can mark the large leaves). Keep humidity at 60–70% and increase air circulation.

Small waxy brown or tan bumps on stems and petioles; sticky honeydew deposits and sooty mould on nearby surfaces. Remove adults manually with a damp cloth. Apply 70% isopropyl alcohol to remaining crawlers and follow with a diluted insecticidal soap spray.

White powdery wax and egg masses hidden along the petioles and in leaf folds; honeydew residue and weakened growth. Dab each mealybug cluster with an alcohol-soaked cotton swab. Spray the plant with insecticidal soap weekly for three to four weeks.