Leaf Miners

Description:
'Leaf miners' is actually a generalized term referring to the larvae of certain moths, flies, and beetles that tunnel through leaves. They feed on the tissue between the upper and lower leaf surfaces, leaving an almost transparent view of their path.

Damage:
Leaf miners are not terribly damaging to ornamental plants unless there is a Severe infestation. When too many of the leaves are damaged the plant may be weakened due to a lack of chlorophyll. For the most part leaf miners just make a few leaves look bad. The exception is leaf crops such as lettuce, spinach, and other edible leafy greens. An infestation on these can ruin a crop.

Prevention: Preventing leaf miners is not an easy task and may only be necessary for leaf crops. The first step is to keep adults from laying eggs on the new transplants or seedlings through the use of floating row covers. Second, remove any weeds as they appear, eliminating living ladders. Tilling and rotating crops will also aide in reducing the numbers of leaf miners.

Management:
Mild Infestations: Damaged leaves on ornamental plants can simply be removed and destroyed. Chemical applications are not necessary at this stage.

Severe Infestations: The larvae are inside the leaf so a systemic insecticide, such as acephate (Orthene) or dimethoate (Cygon) will be the only way to reach them. It is not a good idea to use systemic insecticides on edible plants. Always apply chemicals according label directions.