Orange tortrix (Argyrotaenia citrana), also known as the apple skinworm, is a moth common to coastal regions of the West Coast states.
Cousin to the light brown apple moth (LBAM), orange tortrix and other tortrix moths all roll up leaves to create a protective place to feed.
Orange tortrix identification
Adult orange tortrix are very small, bell-shaped moths when at rest. They are approximately 1/2 an inch long. Both male and female orange tortrix moths are orangish brown with a faint V-shaped marking midwing. Males have darker markings than females. Each female lays 50 to 150 off-white eggs in clusters, usually on the tops of leaves, stems, and fruit. 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.
Orange tortrix damage
Orange tortrix larva are pests of grape, Valencia and navel oranges and other citrus, pear, and apple. Damage to pear and apple fruits are usually limited to mild scarring, but their feeding can lead to other diseases gaining a foothold. The larvae devour any soft plant tissue they can find, including vines, developing buds, young fruit, and new shoots. As they feed, they 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 into mature fruit, providing an entry for organisms that cause bunch rot and other diseases.
Pheromone traps can be used to monitor for male orange tortrix moths. These traps should first be used in late December. There can be up to three generations a year, but these moths prefer temperatures between 45°F and 80°F. Our 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 (pictured below) 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:
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!
I hope this information inspires you to grow more of your own food. You can ask your garden questions on my Home page.