What's eating my pistia stratiotes?

Pistia stratiotes (water lettuce) is a floating aquatic plant troubled primarily by aphids on its rosette leaves and by caterpillars of the water-lettuce moth in warmer regions. Spider mites may attack in hot, dry conditions near the plant. Waterfowl graze on the foliage outdoors. It is generally vigorous and outpaces minor pest pressure.

Dense colonies on leaf undersides and rosette centers; yellowing, distorted leaves and sticky honeydew encouraging mold Spray foliage with a strong water jet to dislodge colonies; use insecticidal soap sparingly to avoid pond contamination; introduce natural predators like ladybirds

Skeletonized or notched leaf edges; silk webbing tying leaves together; present mainly in tropical and subtropical climates Hand-pick caterpillars and egg masses; apply Bacillus thuringiensis (Bt) on foliage — it is safe for pond wildlife at label rates

Leaves grazed down to the waterline; rapid removal of plants from ponds or water features Use pond netting or floating barriers; maintain plant density so the colony can recover despite grazing pressure