Two Agricultural Research Service plant breeders have developed what is believed to be the world's first green leaf lettuce that resists leafminers.

In addition, the variety also is tolerant of the aphid-vectored virus that causes lettuce mosaic, according to a news release.

Salinas, Calif.-based plant geneticists Beiquan Mou and Edward Ryder (now retired) released the variety, known as Salinas 88, after seven years' of lab, greenhouse and field work.

In the process, they screened more than 100 kinds of lettuce from the agency's' Pullman, Wash.-based world collection of lettuces, and from elsewhere.

Adult leafminers (Liriomyza langei) are shiny black flies with a yellow triangle on their backs. They 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.

The lettuce, known among breeders as MU06-857, is the newest in a series of iceberg, romaine and leaf lettuces—and spinach—from the internationally known plant-breeding program at Salinas.

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