It emerges in April–May and lays eggs on the undersides of leaves of beet, spinach, chard, and other greens.

Two to five white cylindrical eggs are laid on the underside of the leaf and hatch four to six days later.

The larvae burrow into the leaf creating a thin trail at first and eventually a blotch or "blister."

The adult fly emerges in two to four weeks and repeats the cycle, creating several generations each year.

Control is cultural, creating a barrier by using floating row covers or removing infestations as soon as they appear and destroying the damaged leaves off site.