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Shop > Beneficial Insects > Leaf Miner Controls

Leaf miners are pests which tunnel through the mesophyll of leaves creating distinctive and squiggly patterns. There are several species of leaf miners attack greenhouse ornamental and vegetable crops. Chrysanthemum, gerbera, gypsophila, marigolds and asters are common ornamentals which leaf miners attack. In Ontario, however, vegetable crops, such as tomato and cucumber, are less commonly attacked. Leaf miner damage is unsightly and, if left untreated, can end up causing serious damage to a plant.

Pest Description

Leaf miner adults are small (2-3mm), shiny, black-and-yellow flies that lay eggs into leaves. The hatched larvae feed between the leaf surfaces mining through the leaves. The larvae are small, pale and yellow maggots. If the leaf is held up to the light or if they are dissected out of the mine, they can be seen clearly. When mature, they cut a hole in the mine and emerge from the leaf. Mating, egg-laying, larval emergence from leaves and adult emergence from pupae tend to occur in the morning, depending on temperature and cloud cover. Leaf miners can be complete their life cycle within 14 days at temperatures of 300C, and up to 24 days at 200C. In summer, they develop faster than usual. Most of their immature life cycle is spent in the pupal stage, which can take more than a week. When temperatures are cool, pupae can survive up to 90 days.

Leaf minder Damage

Found in greenhouses, home gardens and landscaped areas, leaf miners feed between the upper and lower surfaces of leaves, but usually the damage they cause is not life-threatening. Damage can result from the egg-laying and the leaf mines. In ornamental plants, even at low levels of damage symptoms, leaf miners reduce the plants’ value. Moreover, high leaf miner population can affect crop quality and make the crop unsaleable since the mines can reduce the photosynthesis ability of plants.


  • If you see just few sign of tunneling on a leaf, squeeze the leaf at the tunnel between two fingers to crush any larvae.
  • The more healthy the plant, the less chance that leaf miners attack it.
  • It is more effective if you use biocontrol agents on the very first sign of this pest.

Dacnusa sibirica <br> (Ectoparasite)-Not Avaliable
Dacnusa sibirica
(Ectoparasite)-Not Avaliable

<b>Diglyphus isaea</b> <br> (Parasite)
Diglyphus isaea

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