Pear Psylla
Cacopsylla pyricola
A tiny sap-sucking insect that is the most serious pest of pears, both because it spreads the organism behind pear decline and because it fouls fruit with honeydew. It is notorious for quickly developing resistance to insecticides, so prevention and natural enemies matter more here than spraying.
🔎 How to spot it
Adults look like miniature cicadas about a twelfth to an eighth of an inch long, holding clear wings rooflike over a brown to reddish-brown body, with a dark spot near the wing tip. Overwintering adults are darker and larger. The yellow to green nymphs are flat and sit in droplets of their own sticky honeydew. Watch for honeydew, blackened sooty mold, and russeted fruit skin on pears, especially in spring as the buds break.
🥀 Damage it causes
Nymphs feed on leaves and shoots and excrete honeydew that drips onto the fruit, where black sooty mold grows and the skin russets and downgrades. Worse, the psylla injects the phytoplasma that causes pear decline, which saps tree vigor and can kill trees outright. Severe feeding also burns foliage and weakens the tree over time.
🛡️ Prevent it
Keep trees from pushing soft, succulent growth, since heavy nitrogen and hard pruning produce the tender shoots psylla prefer. Protect the orchards natural enemies by avoiding broad-spectrum sprays that wipe them out. A dormant-season oil application smothers overwintering adults and discourages egg laying before the season builds.
🧯 If it is already here
Time a horticultural oil at delayed dormant to coat overwintering adults and eggs, the most reliable home-orchard tool. During the season lean on biological control: the parasitic wasps Trechnites and predators like minute pirate bugs and lady beetles can hold psylla down when not killed off by other sprays. If a chemical is needed, rotate classes, because this insect develops resistance fast.
💡 Good to know
Pear psylla is a textbook case where spraying can backfire, since the insect resists insecticides and the sprays kill the predators that would otherwise control it. A vigorous but not overly lush tree, dormant oil, and protected natural enemies are the backbone of control in a home orchard.
🌱 Plants it attacks
5 plants in the library can be attacked by this pest
For educational and informational purposes only. Pest control advice is general guidance drawn from university cooperative extension sources; always identify a pest positively and read and follow the label on any product before use, especially around food crops, children, and pets.