Resistance of Boxwood Varieties to the Boxwood Leafminer, Monarthropalpus flavus (Schrank)

Abstract

A survey of nine cultivars of Buxus at the United States National Arboretum revealed significant differences in levels of infestation by the boxwood leafminer, Monarthropalpus flavus (Schrank). An analysis of larval survival confirmed high levels of susceptibility in Buxus sempervirens ‘Myrtifolia’ and Buxus microphylla ‘National’ while B. sempervirens ‘Handsworthiensis’ and B. sempervirens ‘Vardar Valley’ exhibited high levels of resistance. Other varieties exhibited intermediate levels of resistance. Field surveys and laboratorystudies indicated that female flies deposited eggs in all cultivars even highly resistant ones. This lack of preference suggests that the mechanism of resistance is antibiosis or phenological asynchrony rather than antixenosis.