5 Different Leaf Miners: Which one will damadage your plants, veggies and flowers?

Certain insects feed for the entire larval period, while others pupate within the leaf mine. Still few have the larvae cut their way out from the leaf to pupate in the soil.

Depending on the pattern of the mine they produce, the insects are classified as a Serpentine, Blotch and Tentiform. The Serpentine leaf miners create a snake-like pattern across the leaf. The mine widens as the insect grows.

The Blotch leaf miners are rounded irregularly. They have a subgroup called Tentiform that produces bulging blotch-type mines curving upwards like a tent as the damaged tissue dries up.

Some mining patterns are a combination of any of the above classification. For instance, there are species that initially produce Serpentine pattern and eventually cease to start mining in Blotch pattern.

When the leaves have been eaten by insects, that portion of the plants withers and die. However, the injuries done to the plant do not have a negative impact on its health.

In addition, the insects have a natural control system which checks their populations before too much damage has been done to the plants.

The injuries that the insects cause to the plants are sometimes mistaken to be a creation of leaf spotting fungi or other abiotic issues.

To determine whether the leaf is mined by insects, the damaged area is pulled apart. If the hollow area exposes insects and or its droppings, then obviously the leaf is injured by miners.

Leaf spotting fungi, when they wreak havoc, makes the leaves to collapse without any tunneling.

• The common leafminers of trees and shrubs are Sawfly, Elm, Tentiform, Lilac, Needleminer, Aspen, Poplar blackmine, and European Elm Flea Weevil.

• Sawfly leafminers chew on the surface of the leaves. The adults are dark-colored and small. They are non-stinging wasps that insert eggs into the newly-formed leaves. The larvae produce huge blotch mines during late spring.

• The Elm leafminer is common in Front Range cities where the insect develops on American, English and Siberian Elm trees. Some of its species include the Hawthorne leafminer, Birch leafminer and Alder leafminer.

• Tentiform leafminer is common in Willows, Poplars, Hackberry, Apple and Cottonwoods. However their outbreak is rare because it is constantly bombarded by parasites and other natural enemies.

• A Lilac leafminer is small and produces a blotch mine while it folds the edge of the leaf. Its variant is the Boxelder leafminer which produces identical leaf injuries.

Some minute moths have larvae that evolve in the needles of the conifers, and hence called needleminers. The needles when affected turn brown. These insects are common among Lodgepole Pine, Pinyon and Spruce.

Delicate and winding—these are the characteristics of the works of an Aspen leafminer whenever it feeds on the upper leaf surface of Aspen leaves. The injury is also significant and noticeable.

A Poplar blackmine beetle produces a black blotch in Poplar leaves. The adults gnaw small holes on the leaves, which are only minor.

The European Elm Flea Weevil is the newest leafmining insect to settle in Colorado. The larvae produce a leaf mine in Elm trees resembling an Elm leafminer sawfly.

The mine of this insect starts from a leaf vein, develops into a serpentine and finally closes in blotch pattern.

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