There are numerous species of leafminers: the American serpentine leaf miner, the tomato leaf miner, the pea leaf miner as well as insects in which the larval stage lives in and nourishes itself from the plants leaf tissue.
Punctures caused by females during the feeding and oviposition processes can result in a stippled appearance on foliage, especially at the leaf tip and along the leaf margins. However, the major form of damage is the mining of leaves by larvae, which results in the destruction of leaf mesophyll. The mine becomes noticeable about three to four days after oviposition and becomes larger in size as the larva matures. The pattern of mining is irregular. Both leaf mining and stippling can greatly depress the level of photosynthesis in the plant. Extensive mining also causes premature leaf drop, which can result in lack of shading and sun scalding of fruit. Wounding of the foliage also allows entry of bacterial and fungal diseases.
The pattern of the feeding tunnel and the layer of the leaf being mined is often a good diagnostic of the responsible pest. The leaf miner is capable of breeding throughout the year especially in heated greenhouses. It is an extremely virulent pest and when in outbreak proportions, it may severely disrupt photosynthesis in the plant leaves eventually leading to dry-out and defoliation.
There are specific natural enemies for different species of leaf miners.
For more information contact your local BioBee field agent.