Leafminer

Mines in the leaves of your vegetable or ornamental crops? That must be the work of leaf miners as they cause severe damage to your plants. Leaf miners are the larvae of the dipterous insect of the genus Liriomyza. The most common species are the tomato leaf miner Liriomyza bryoniae, the serpentine leaf miner L. trifolii or the pea leaf miner L. huidobrensis. Time to get rid of this pest with biological control!

What damage can leaf miners cause?

Female adults makes round mines in the upper surface of the leaf with their ovipositor to extract plant sap. That’s how feeding dots occur.
The mines reduce the photosynthetic capacity and the aesthetic value of the plant and cause withering or leaf shedding.
The feeding dots can be an entrance for several diseases.

How to control leaf miners?

To monitor leaf miners, you can rely on Biobest’s Bug-Scan^®.

For biological control of this species, you can introduce:

Parasitic wasps such as Dacnusa-System and Diglyphus-System;
Nematodes such as Steinernema-System.

What are the characteristics of leaf miners?

The 2 to 3 mm adult females have a black and yellow colour with a conspicuous yellow dorsal spot.
Males are a little smaller, don’t have an ovipositor and rely on feeding dots made by the females.
The tiny eggs are oval and creamy white and are laid in the feeding dots.
The young larvae start digging mines in the leaves immediately after hatching.
The recently hatched larvae are about 2 mm long. They are transparent but become dirty white to yellow ochre as they grow.
In order to pupate, the larvae cut a hole in the leaf cuticle and wiggle their way out.
The pupae are yellow to reddish-brown and remain on the leaf or fall off.

What about the leaf miners’s life cycle?

Leaf miners can lay up to several hundreds of eggs.
Leaf miners have 6 development stages: egg, 3 larval stages, pupa and adult.
The development from egg to adult depends on the temperature and takes 2 weeks at 30 °C/86 °F and 7 weeks at 15 °C/59 °F.
Adult females live for 1 to 2 weeks.