Lace Bug in the Pacific Northwest

Lace Bug has been in the State of Washington and Oregon since 2009. Increasing in their populations, this pest has devistated Rhododendrons and Azaleas in the Pacific Northwest. The Rhododendron-Lacebug has one generation per year. The Azalea- Lacebug has several generations per year, which is making it difficult to keep up with the damage they are doing to the Azaleas in our area.


Lace Bugs are a sucking pest. This causes stippling and bleaching of the leaves on infested Rhododendron and Azalea leaves by late summer. Adults and nymphs leave the underside of the foliage with a dark excrement. Thrips and other plant pests also produce both leaf stippling and dark excrement. Examine the lower leaf surface to determine what type of insect is causing the leaf damage. Mites also stipple leaves, but mites do not leave the dark excrement. Miticides cannot control Lacebug. It is important to use insecticides that target the pest you are trying to control.


Provide proper cultural care so plants are vigorous. No treatment will restore stippled foliage, which remains until pruned off or replaced by new growth. If damage has previously been intolerable, monitor plants early during subsequent seasons. Take action when populations begin to increase and before damage becomes extensive.


Natural enemies of Lace Bugs include Assassin bug, Lacewing larvae, Lady Beetles, jumpingspiders, Pirate bugs, and Predaceous Mites. These predators should appear in sufficient numbers when lace bugs become abundant. Their preservation, however, is an essential part of a long-term integrated pest management program. Mulching soil with an organic compost material, shading plants from afternoon sun can discourage populations of Lace Bug. If applying pesticides, using only short-persistence materials such as oils and insecticidal soaps. This will protect the beneficial predators and parasites, keeping the natural biological control in place. Hiring a Licensed Pesticide Appplicator is always a good idea if your’re not familier with these products, and how to handle them.


Grow plants well adapted to the site. Plants in hot, sunny locations are more likely to have more Lace Bug pressure than plants in shady areas. Provide adequate irrigation to improve plant vigor. Prune out damaged foliage if the discoloring is intolerable. Do not remove more than a small percent of a plant’s branches during one season and use good techniques so that pruning does not injure plants.

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