Bay Sucker
Trioza alacris
A sap-sucking psyllid that feeds on bay laurel, causing the leaf edges to thicken, curl downward, and yellow into tubular galls. The damage is mainly disfiguring on a culinary or ornamental bay, and a healthy tree tolerates it, but heavy infestations make the foliage unsightly.
🔎 How to spot it
The adult is a small psyllid about an eighth of an inch long with pointed wings and dark-tipped antennae, looking like a pale brown aphid that jumps. The nymphs feed inside the rolled leaf margins and produce white, waxy, woolly deposits. The most obvious sign is the curled, thickened leaf edge rather than the insect itself.
🥀 Damage it causes
Feeding by the nymphs makes the leaf margin thicken and roll downward into a tubular gall, often affecting only one side or half of a leaf, which then yellows and later turns brown. Inside the rolled margin are the nymphs and their white wax, and severe infestations leave the bay looking distorted and patchy. The injury is cosmetic on an established tree but reduces the quality of leaves harvested for cooking.
🛡️ Prevent it
Pick off and destroy galled, curled leaves and shoots as they appear to remove the sheltered nymphs and reduce the next generation. Inspect new growth in spring, since the overwintered adults attack the tender flush. On a small bay, repeated hand removal often keeps the problem in check.
🧯 If it is already here
A contact material such as horticultural oil, insecticidal soap, or pyrethrin can be applied against the overwintered adults in spring and again when cast skins show a new generation starting, aiming to hit the insects before the leaves close around them. Because the nymphs hide inside the rolled margins, coverage and timing matter. On culinary bay, prefer removal and soaps or oils and follow the label for harvest.
💡 Good to know
The bay sucker is specific to bay laurel, and the female lays into the leaf margin, which rolls inward to form a tubular gall that can hold many eggs. Fresh galls are pale green with a pink or red tint before they yellow. Because the damage is mostly cosmetic, light infestations on an ornamental bay can be tolerated.
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.