Orange Tortrix Moth

Orange tortrix moths, also known as apple skinworms, are common to western North America, northern Africa, and eastern European countries. Orange tortrix larvae are pests of grapes, citrus, strawberries, pears, apples, and avocados.

Garden tortrix moth (Wildreturn) CC BY 2.0

Cousin to the light brown apple moth (LBAM), orange tortrix (Argyrotaenia citrana; Argyrotaenia franciscana) and other tortrix moths all roll up leaves to create a protective place to feed.

Orange tortrix identification

Adult orange tortrix moths and their cousins (amorbia) are small, bell-shaped moths when at rest. They can be 1/2” to 3/4” long. Both male and female orange tortrix moths are orangish brown with a faint V-shaped marking midwing. Males have darker markings than females.

Female orange tortrix (Simon Hinkley & Ken Walker) CC BY 3.0 au

Male orange tortrix (Simon Hinkley & Ken Walker) CC BY 3.0 au

The larvae are 1/2 inch long and greenish to straw-colored. Larvae have a tan head and a prothoracic shield. Prothoracic shields are hard plates that wrap partially around the larva’s body where a neck would be (if they had a neck). Orange tortrix larvae are very active and will wriggle backwards or sideways, drop to the ground, or hang by a silken thread if disturbed. Eggs are pale green, oval, and flat, with a patterned surface.

Tortrix lifecycle

Each female lays overlapping clusters of 50 to 150 eggs per cluster, usually on the tops of young leaves and stems and on immature fruit. Nine days later, the eggs hatch. Young larvae move to tender new growth where they create a protective silk nest under which they can feed. Larvae go through 5 to 7 developmental stages, or instars, as they grow from 0.08” to 0.5” in length. Once they have eaten their fill, tortrix moth larvae spin a cocoon around themselves, where they go through a complete metamorphosis in 1 to 3 weeks, depending on environmental conditions. You might see any of these life stages throughout the year. Orange tortrix moths have 2 - 4 generations per year.

Orange tortrix damage

Tortrix larvae devour any soft plant tissue they can find, including vines and tendrils, developing buds, young fruit, and new shoots and bark. Twig girdling can occur and leaf holes may also be visible. As they feed, tortrix moth larvae often create protective webbing around new leaf clusters or they may roll, fold, or tie a leaf down over a fruit to create a safe place to feed. Older larva will burrow deeply into mature fruit, providing an entry for organisms that cause bunch rot and other diseases (and a horrible surprise, if you don't notice the hole). Damage to fruit is most commonly seen at the stem end, often causing fruit to drop.

Orange tortrix management

Orange tortrix have many natural enemies, including assassin bugs, damsel bugs, lacewings, and pirate bugs, as well as birds. Several parasitic wasps and tachinid flies parasitize tortrix.

Pheromone traps can be used to monitor for male orange tortrix moths. These traps should first be used in late December. These moths prefer temperatures between 45°F and 80°F. Scorching summers usually send these pests into dormancy. If pheromone traps are used, you will need to know the difference between the orange tortrix pest and the garden tortrix, which is not a pest.

​Garden tortrix have a light colored band in front of the dark V and they have dark, crescent shaped marks on the outer edge of each forewing. There’s no sense treating for orange tortrix if your trees are being visited by garden tortrix. If pheromone traps indicate that you have orange tortrix moths, use these tips to help protect your vines and fruit trees:

• monitor trees and vines for rolled leaves
• dispose of mummies (these provide overwintering sites)
• avoid using broad-spectrum pesticides that kill off natural predators [Tortrix population booms are common after spraying organophosphate or carbamate insecticides, which kill off predators]
• grow coyote bush near vulnerable trees to provide habitat for the Exochus wasp
• remove nearby poppies, mustards, lupine, mallow, curly dock, and filaree (Erodium) before new shoots develop in spring
• spray Bacillus thuringiensis (Bt)​

While the orange tortrix moth is generally not a big threat to your garden or landscape, it can cause problems, so keep a look out for those rolled leaves.