Pest Control: Leaf Miners

There are numerous species of leaf miners including the American serpentine leaf miner, the tomato leaf miner (tuta absoluta), the pea leaf miner, and the chrysanthemum leaf miner. 

                  

DAMAGE

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.

The primary enemy of the leaf miner is the BioDiglyphus.

(Click the name of the beneficial insect for additional information) 

BioDiglyphus - (Diglyphus isaea) is an ectoparasitic wasp that parasitizes leaf miner larvae in field and greenhouse crops.

In addition to these insects, the following insects also target leaf miners along with their primary enemies:

BioSf - An entomopathogenic nematode containing infective juveniles of Steinernema feltiae in an inert carrier.