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.