Avocado Leafroller
Amorbia cuneana
The caterpillar of a tortricid moth, also called the western avocado leafroller, that ties leaves together or ties leaves to fruit with silk and feeds inside the shelter. It is mainly a pest of avocado, and most feeding is on foliage, but scarring of the fruit surface is what causes economic loss.
🔎 How to spot it
Adults are about an inch long with variably colored forewings that are mostly orangish to tan with dark markings, larger than the similar orange tortrix. The caterpillars are yellowish green when young and become darker green as they mature, growing up to about an inch long, and can be told from other avocado and citrus caterpillars by a dark horizontal line on each side of the head and another above the first pair of legs. Rolled and webbed leaves are the first clue.
🥀 Damage it causes
The larvae roll and tie leaves together with silk, or tie leaves to fruit, and feed within this protected shelter, consuming the leaf from the center or the edge. Where young larvae feed under or around the fruit calyx, the rind develops discolored scars that resemble thrips damage. Leaf feeding is mostly cosmetic, so the real concern is the fruit scarring.
🛡️ Prevent it
Scout for the silk-tied leaf shelters and clip off and destroy infested foliage and any egg masses while numbers are low. Conserve the many natural enemies that keep this caterpillar in check by avoiding broad-spectrum insecticides. Light leaf feeding can be tolerated on a healthy tree.
🧯 If it is already here
If only a few caterpillars or egg masses are present, crush them or remove the infested foliage and dispose of it. When caterpillars are abundant, Bacillus thuringiensis or spinosad sprayed to thoroughly cover the outer canopy gives good control while sparing most beneficials. Numerous natural enemies usually hold the leafroller down unless disrupted by harsh sprays.
💡 Good to know
Amorbia develops through two to three generations a year in southern California and the San Joaquin Valley. Besides avocado it occasionally damages citrus grown nearby and also feeds on bay laurel, hollyleaf cherry, madrone, manzanita, photinia, and pyracantha. The dark line across the head is the quickest way to confirm the larva.
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.