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Psyllids are aphidlike insects that secrete sticky honeydew. Some species produce
white wax, distort leaves and shoots, stunt plant growth, or cause defoliation. Psyllid management includes
proper plant care, conserving natural enemies, and applying low-toxicity insecticides when needed. Most plants
can tolerate low to moderate numbers of psyllids.
Plants commonly affected include:
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Acacia, boxwood, eucalyptus, eugenia, pepper tree, and some other ornamentals.
- Pear, potato, and tomato.
Damage resembles that from some aphids, scale insects, and whiteflies. Look for:
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- Abundant sticky honeydew excreted by psyllids as they suck plant sap.
- Black sooty mold growing on the honeydew.
- Curly or powdery wax or (in certain species) crystallized covers called “lerps.”
- Distorted or galled leaves or shoots or prematurely dropping foliage.
Learn to recognize psyllids:
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- Adults are 1/10 to 1/5 inch long and hold their wings rooflike over their bodies.
- Adults are quite active, often jumping away when disturbed.
- Nymphs are flattened, oblong to round, and can move or (in pit-making species) are immobile.
- Nymphs of several species feeding on
eucalyptus are hidden under hardened covers (lerps).
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To reduce problems, use an integrated program:
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Provide plants appropriate environmental conditions and cultural care, especially proper irrigation; conditions
vary for each location and plant species.
- Choose plant species or cultivars that are not infested by psyllids or are less susceptible to these
pests, such as certain acacia and eucalyptus.
- Learn how to recognize and conserve psyllid parasites and predators. Certain psyllids may be controlled
biologically unless natural enemies are disrupted.
- Avoid stimulating succulent growth. Especially avoid fertilization and unnecessary pruning.
- For topiary eugenia, shear growing tips at about 3-week intervals and leave eugenia clippings as mulch
on the ground for at least 3 weeks to allow parasites to emerge.
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Do not treat plants with insecticides unless you have an intolerable psyllid infestation.
- Avoid insecticides that injure natural enemies, including lady beetles, pirate bugs, and parasitic wasps.
- If you treat, select insecticidal soaps, oils and other least toxic products, or use a systemic insecticide
(preferably soil-applied) for especially intolerable problems.
A portion of a redgum leaf where psyllids have formed a waxy cover called a “lerp” under
which nymphs feed.
Minimize the use of pesticides that pollute our waterways. Use nonchemical alternatives or less toxic pesticide products whenever possible. Read product labels carefully and follow instructions on proper use, storage, and disposal. |
