Angular-winged katydid

Systematic position: The angular-winged katydid (Microcentrum retinerve) is a member of the order Orthoptera and the family Tettigoniidae. This insect is a notable agricultural pest, particularly in North America, known for its distinct leaf-like appearance and its consumption of foliage on various woody plants.

Crops and economic impact: This pest primarily affects fruit trees such as apple, peach, pear, citrus, and occasionally grapevines. Both nymphs and adults consume foliage, often leaving irregular, ragged holes. While minor infestations are rarely lethal, heavy populations can significantly defoliate young trees and damage the epidermis of developing fruit, reducing marketability.

Biology and life cycle: The life cycle involves incomplete metamorphosis. Females lay flat, oval eggs in double rows along the margins of leaves or small twigs, resembling an overlapping stitch. Nymphs hatch in the spring and undergo several molts before reaching the adult stage. The adults possess wings that perfectly mimic the appearance of a leaf, providing excellent camouflage against predators.

Character of damage: Damage is usually observed during the summer months. Because they are primarily nocturnal, they are seldom seen during the day, making the jagged leaf margins the primary indicator of their presence. They are particularly destructive when populations reach high densities, as they can feed on tender green shoots and buds, stunting the tree's growth.

Control measures: Management strategies rely on early detection and physical removal where possible. During the dormant season, inspect twigs for egg masses and prune them out. In cases of significant infestation, application of registered insecticides is recommended, targeting the younger nymph stages. Promoting biodiversity in the orchard helps maintain natural predator populations like spiders and birds that naturally keep katydid numbers in check.

• Visual inspection of foliage for characteristic egg clusters.
• Pruning infested branches during the dormant winter period.
• Use of contact insecticides targeting nymph populations.
• Encouraging natural biological control agents in orchards.