Oak Ribbed Casemaker

You will find small caterpillars creating distinctive ribbed cases from leaf fragments and silk on the undersides of oak leaves. Each larva constructs a portable case roughly one-quarter inch long with lengthwise ribbing. Cases are light tan to brown. Larvae graze on leaf tissue adjacent to their cases, creating window-like feeding patterns. Multiple generations occur throughout the growing season on host oaks.

Damage is generally light and cosmetic on most oaks. No control is needed for tree health. Hand-prune heavily infested leaves if appearance is objectionable. Encourage parasitic wasps and predatory insects by avoiding broad-spectrum applications. Leaf drop is natural and does not require intervention. Most oaks tolerate casemaker populations without visible impact on growth or vigor.