Common names: Grape Leafroller, Orange Tortrix
Scientific name: Order Lepidoptera, family Tortricidae, Argyrotaenia citrana
Size: 3/4" to 1"
Identification: Caterpillars are greenish yellow to pale straw color. They fold the leaves together for protection while they feed inside. When the leaves are pulled apart, they wiggle fast and drop from sight. Adults are orangish to gray moths. The caterpillars wriggle vigorously when touched.
Biology and life cycle: Cream-colored eggs are laid in groups that overlap like fish scales. And they have overlapping generations. The first damage is in early summer.
Habitat: Orchards and vineyards.
Feeding habits: Attacks grapes, citrus, stonefruit, bougainvillea, apples, and strawberries. Besides webbing leaves together, they also build webs in and feed on bunches of grapes. Their web can easily be mistaken for a spider web.
Economic importance: The caterpillars fold the leaves together in perfect halves and hold them tightly together with webbing while feeding on a thin outer layer; they avoid eating holes all the way through the leaves and exposing themselves. If no measure of control is used, they will soon fold every leaf on the grapevine.
Natural control: Wasps, tachinid flies, and general predators that feed on their eggs.
Organic control: Healthy, adapted varieties of grapes. Pheromone traps, and Liquid Fire Ant Control and plant oil products.
Insight: This is a very interesting but troublesome insect that is difficult to photograph.