What Are Leaf Miners And How Do I Identify Them?
Leaf miners are the larvae (maggot stage) of small flies and can be as dense as 6 or more larvae per leaf. The adult flies are roughly 2mm in length and they are grey-black with a yellow underneath. The flies can be seen at any time of the year in greenhouses but outdoors it will generally be between July and October.

The adult fly will lay an egg under the surface of the leaf. This will cause a white spotting on the upper surface of the leaf. The egg will then hatch into a larvae inside the leaf and will tunnel through the leaf creating a mine, which can be seen on the leaf as a yellow/brown slightly raised tunnel. The larvae will turn into a pupae in the mine and finally the adult emerges. This lifecycle will be completed in three weeks.

What Damage Do They Cause?
Leaf miners can be a significant problem as they cause damage to pot and bedding plants as the larvae tunnel within the leaf tissue. The mines look unsightly and the plant cannot photosynthesize as well as it should do. This will mean that the plant is of much poorer quality. The mines will start of quite thin but they will become thicker as the larvae feeds and grows. If the problem is allowed to take over. The plant will begin to lose its leaves and may even die.

We recommend using a specialist insecticide such as Decis Protech (an excellent broad spectrum insecticide) or Smitten (a contact and translaminar insecticide and araicide). 

For more information on controlling Leaf Miners, please get in touch with our sales team on 01522 246491.