Lily Borer

The lily borer (also known as the amaryllis borer) can be identified by its distinctive black-and-yellow banded body of up to 40mm in length.

Lily borer host plants are: Clivias, agapanthus, crinums, haemanthus, amaryllis and other summer bulbs.

Damage caused is: Leaves with holes and chunks eaten out of them. You will also observe tunnels in leaves where hatched larvae have entered and fed while tunnelling their way into the bulb.

If uncontrolled, they will eventually kill the whole plant. Collapsing bulbous plants are normally a sure sign of lily borer infestation, but by this time it might be too late to save the plant.

When are they active?

The white moths start laying their eggs on the underside of the leaves in early September (although in warm subtropical climates they do it year-round). In the warmer months, newly-hatched larvae will immediately start feeding at night and on dark overcast days.

Controlling these pests

The best plan is to start spraying preventatively in mid-September with two applications per month until March. Products to use are Margaret Roberts Biological Caterpillar Insecticide or Makhro Cyper, which are both contact and stomach insecticides. Spray at late dusk or at night.

The Gardener