Thrips on prayer plant
What's Happening
Unique symptom of thrips feeding on pigmented Maranta foliage. Thrips rasp and suck leaf juices, rupturing epidermal cells and triggering the leakage of anthocyanin-rich sap, which appears as a 'purple residue' or dark sticky spots. This is often accompanied by silvery stippling or linear scarring.
How to Fix It
- 1
Perform a 'Magnification Check' on leaf undersides for tiny, slender motile insects and black fecal specks (frass).
- 2
Wipe leaves with 70% isopropyl alcohol to remove residue and kill crawlers.
- 3
Deploy blue sticky traps (more attractive to many thrips species than yellow) for monitoring.
- 4
Apply Captain Jack's Dead Bug Brew (Spinosad) or Bonide Systemic Granules (Imidacloprid) for severe infestations.
What You'll Need
How to Prevent It
Inspect new growth weekly; maintain high humidity (60%+), as thrips thrive in dry indoor environments; quarantine new plants for 14 days.