To combat leafminers, Agricultural Research Service plant geneticists Beiquan Mou and Edward Ryder (now retired) developed the world's first leafminer-resistant green leaf lettuce.
Adult leafminers, which are shiny black flies with a yellow triangle on their backs, ruin leaves when they puncture them to feed on sap. Females add to the damage when they lay tiny oval eggs inside the leaves. Wormlike larvae hatch from the little eggs and, as they feed, create the mine-like tunnels for which the pest is named.
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