Lace bug is a serious pest in gardens, attacking the leaves of azaleas and rhododendrons. The damage it causes is seen as bronzing or silvering on the top of the leaves (see image above), but the pest itself is active underneath the leaf.

If you look on the underside of a damaged leaf, the tiny pest along with frass (insect poo) and webbing will be visible. To see the insect clearly, use a hand lens or magnifying glass. The pest gets its name from its lacy wings, which are clear but marked with black. Clear or dark wingless insects spotted near the adults are juveniles known as nymphs.

Plants that are stressed, particularly by very hot or dry conditions, are most susceptible to lace bug attack. If a plant is attacked in one year, it will probably be attacked in subsequent years. This is because the pest survives over winter as eggs, which stay on the plant and are then ready to hatch when spring arrives.


Left is a close-up of a tiny azalea lace bug... and at right you'll see the damage they cause!


How to control lace bugs

  • Plant azaleas and rhododendrons in semi-shaded positions.
  • Keep plants well-watered, especially when conditions are very hot and dry.
  • Feed azaleas and camelliass in spring with a specialised food to encourage strong growth. Flower Power recommends Neutrog's Kahoona for Camellias, Gardenias, Rhododendrons, Azaleas & Other Acid-Loving Plants.
  • Prune off the badly affected branches and put them in a bag in the rubbish bin.
  • Spray the underside of the leaves with a registered pesticide such as Yates' Baythroid Advanced. Follow the instructions on the container for repeat applications.
  • To try to reduce repeated attacks, spray in spring when first signs of the pest are seen (check undersides of leaves regularly).


Pests similar to lace bug

Two-spotted mite is another pest that feeds on the underside of foliage and causes bronzing and silvering of leaves. It can attack azaleas and rhododendrons along with a large range of shrubs, perennials and annuals. Fuchsias, strawberries, roses, some vegetables and indoor or potted plants are often damaged by two-spotted mite.

This small pest can also be seen using a hand lens to examine the underside of damaged leaves. It is tiny with two black spots on each side of its body which is yellow to green in colour. This insect is a mite – a spider relative – so adults have eight legs. It, too, will be surrounded by frass, juvenile stages and webbing.

Control as for lace bug using a registered pesticide for mites such as wettable sulphur or Yates' Nature's Way Vegie & Herb Spray Natrasoap, spraying under the leaves.

A leaf showing signs of two-spotted mite infestation.