Columbine Leafminer: Appearance, Territory, Damage and Life Cycle

Latin Name: Phytomyza Minuscula

Appearances: Columbine leafminers are little, dark-colored flies that feed on the leaves of columbine plants. Adult leaf miners have a similar appearance to house flies. They’re about a tenth of an inch long on average. In addition to being black or grey in colour with yellow stripes and clear wings, they are also black or grey in colour. Larvae resemble small worms or maggots, measuring about 13 inches long and tinted green or pale yellow.

Host Plants: Columbines, perennial sunflowers, daisies, and Veronica are some of the herbaceous plants that house leafminers.

Territory: Gardeners rarely see columbine leafminers, which are little, dark-colored flies endemic to North America. The most frequent species found in the Midwest is Phytomyza aquilegivora, which creates unique serpentine paths in the leaves.

Damage Caused: Phytomyza Minuscula, or columbine leafminers, are widespread garden pests. The little brown to black flies lay their eggs on the underside of the leaves, and as the maggots mature, they tunnel through the leaves. The leafminers may disfigure every leaf in a clump on occasion. Columbine leafminer may attack the leaves so intensely that more than 75% of the leaf tissue is damaged as the plants begin to produce lovely flowers. This weakens the plants, which can lead to their death.

Life Cycle and Habits: The little brown to black flies lay their eggs on the underside of the leaves, and as they grow, their maggot’s tunnel through the leaves. The leafminers may disfigure every leaf in every clump at times. When the maggots have finished feeding, they cut a crescent-shaped hole in the leaf and pupate outside in a little seed-like capsule known as the puparium. A new generation of leafminer flies emerges in roughly two weeks to continue the “cycle of existence.” From May through September, there are up to five generations. This pest spends the winter as pupae in its puparia. The egg, larva, pupa, and adult moth are the four stages of the citrus leafminer’s life. Adults are harmless to plants and only live for one to two weeks. Adult moths are most active in the morning and evening, resting on the undersides of leaves throughout the day, however they are rarely seen.

The newly emerged legless larvae will begin feeding by burrowing into the inside of the leaves. The larvae will gnaw through the leaf surface, fall to the ground, and pupate when they are fully grown. Because the leafminer’s life cycle lasts 30-40 days, there might be 3-4 generations per year that overlap.