Boxwood leafminer

Inspect boxwood leaves for blistered puffy appearance on undersides with orange or reddish tint; upper surface shows pale yellow or light green speckles where tiny larvae tunnel between layers. Heavily mined leaves turn brown and drop prematurely by late summer. Look for this damage on common boxwood throughout growing season.

Prune out and destroy heavily mined leaf clusters to remove developing larvae, particularly effective in spring when blisters first appear. Apply horticultural oil in late March to smother overwintering pupae before adults emerge. If mines appear later, remove and destroy infested leaves rather than spraying; boxwoods tolerate defoliation well. Repeat infestations may warrant resistant species.