Leaf miners

by Kate Bradbury

Leaf miners literally 'mine' leaves, tunneling through them and eating them from the inside, before pupating and emerging as an adult...

Leaf miner on chrysanthemum leafLast year I wrote a blog about cuckoo spit, in which I documented the fauna that had appeared in my garden after I had transformed it from a paved courtyard. I celebrated the arrival of butterflies, birds, froghopper nymphs and moths, but was less pleased by the discovery of slugs, snails and leaf miners. One commenter suggested I take a closer look at leaf miners, which he described as "fascinating".

Leaf miners literally 'mine' leaves, tunnelling through them and eating them from the inside, before pupating and emerging as an adult. They are usually species of fly or moth, but some are types of beetle or sawfly. There are flies that tunnel through spinach and beetroot, moths that fashion phallic-shaped 'cases' from leaves of apples, beetles that leave red blotches on hawthorn leaves and, of course, moths that devastate horse chestnut trees.

On the whole, I like leaf miners. I don't enjoy finding them in my saucepan after harvesting spinach in the dark, and I was upset when they mined my aquilegias to death (they weren't the healthiest of specimens to start with). But, despite these hiccups, I'm happy to share my garden with them. Some of the patterns they make on leaves are quite beautiful – I like to think of them as nature's graffiti.

As well as such interesting fauna, lots of plants have appeared in my garden since I transformed it from a courtyard. Some of them, such as the spear thistle and creeping thistle, are less welcome than others, but I can't get rid of them now – they've been decorated with the most beautiful markings by a leaf miner.

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Talkback: Leaf miners
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Gardeners' World Web User 30/09/2011 at 18:38

I generally am a live & let live sort of person with most leaf miners as with other garden insects/pests but I do get really rather cross about the devastation that miners always do to my Iris foetidissima leaving almost white stripy leaves in their wake. Every year I swear I am going to resort to chemicals...........but I never do!

Gardeners' World Web User 30/09/2011 at 18:55

I hate them as they devastate my beetroot (I prefer to eat the leaves than the root). I don't think you can stop leaf miners with chemicals, as they live inside the leaf so are protected from anything you can throw at them. The best way I have found is to disrupt their life-cycle by rubbing out the eggs (typically on the back of the leaf) every few days. This keeps their numbers down but never seems to quite wipe them out, as I must miss a few.

Gardeners' World Web User 01/10/2011 at 09:45

You know its funny you should post about leaf miners. I've never really been plagues with them before, however since the slugs ate all my seedlings that I blogged about growing and I bought some form the local garden centre they have become infested with leaf miners. I have found that pyrethrum does the trick though and whats more its natural!! Jess

Gardeners' World Web User 06/10/2011 at 20:29

perhaps we should really inspect everything that we buy for the garden or given, if i give plants away i inspect them first and always treat the plants with vine weevil killer to give them a good chance of survival, hope everyone has a good winter.

Gardeners' World Web User 28/11/2011 at 18:44

Your picture looks just like he tracery I have found on a lot of conkers this year, Kate. They look more like Pony Piebalds than Horse Chestnuts, if that makes sense. It is the first year I have noticed this mottling of the normally rich brown colouring.