Advice - What is eating my waterlily leaves?

Care for your waterlilies 1   2   3   4   5   6  

Pond pests found eating waterlily leaves:

1. China Mark Moth

  • Look for large, neat holes on the edge of your waterlily leaves.
  • The caterpillar will cut holes in the leaves on the edges or centrally where the stem joins the leaf.
  • These pieces will be placed on the underside of the leaf to cover the pupa. Each  develops under its own patch of bitten off leaf.
  • The pupa can be exposed by lifting off the patch. To control an infestation you should destroy the pupa.
  • All the affected leaves should be removed and burned.
  • You are not finding the adult by doing this but you are removing future generations so this is a long term plan.

2. Pond Snails

  • Waterlily leaves can be disfigured by the Great Pond Snail - (the pointed shelled snail not the circular shell of the ramshorn snail).
  • Above is a photo of the jelly capsules of snail eggs on the back of a waterlily leaf.
  • Remove the egg capsules from the leaf with a thumbnail to keep the population under control or by removing the whole leaf to the compost bin.
  • To remove snails from your pond - float a juicy lettuce leaf on the water surface overnight. Next morning carefully lift it off and you will bring with it lots of pond snails grazing happily.

3. Waterlily Beetle

  • The Waterlily beetle and its larvae eat long slit like holes in waterlily leaves or chew around the leaf edge - the adults are 1/4" long(5mm) and are yellow/brown.
  • They emerge from winter hiding places in nearby foliage in May and lay small white eggs on the top surface of the waterlily leaves.
  • To kill these eggs drown the plant leaves for a few days under the water or spray a dilute mixture of washing up liquid over the infected leaves. (10ml washing up liquid in 250ml water). Apparently a mix of cooking oil in water will do the same job.

4.  Waterlily Aphid

  • Aphids may also affect soft and succulent leaves of the water lily. They are minute - 2mm in size and brown/black & will suck the sap from the leaf.
  • The adults and eggs overwinter on Prunus plants - Cherries, Plums and Blackthorn. They hatch in Spring until mid summer when they can fly to the waterlily plant.
  • The leaf will become yellow and often distorted which allows the aphids to infest the underside of the leaf too.
  • Drown the aphids by dropping the planted basket to the bottom of the pond for two or three days.
  • Or spray the waterlily leaf with the detergent mixture described above and they will no longer be able to fly or mate.
  • For better long term results spray the host tree in December with Winter Tree Wash by Growing Success or Vitax to reduce the number of overwintering eggs.