A mechanical simulation technique was utilized to produce damage in terminal buds of ‘Spanhoma’ variety peanuts, Arachis hypogaea L., which resembles quite closely that of Stegasta bosqueella (Chambers). The ability of leaflets to compensate for this damage decreases as they enlarge from terminals. Damage to very small leaflets (area 2) results in much less reduction in mature leaf area than the same extent of damage to larger leaflets (150–450 mm2). Feeding of the rednecked peanutworm through the larval development period results in a mean reduction in mature leaf area of 3993 mm2 (≈4 leaflets)/individual.