Friday, October 26, 2012

Swiss chard leaf miners

Trouble in chard town...

Leaf miners.

I mean, Why? I've never had chard before. So where have the miners been lurking till now? Did they just stumble upon this roof? Did someone start a miner Meet Up group? 

I noticed about a week ago that the chard was beginning to look peaky. Eh, too much water, I thought. But it has become worse, and today closer inspection showed leaf miner action quite clearly - that early tell-tale, transparent squiggle, leading to loss of colour and structure and this awful, flaccid paleness. Off-with-their-heads: I saved all the good leaves (and we ate them for dinner in minestrone) and pulled up the rest. Otherwise I'll have leaf miners next year, pupating in the soil. I may have them, already. I bastardi.

In a word, Ugh.

The good new is that I now have three free pots! An excuse for late-season seed experimentation.

It ain't over till it's over.


  1. I have seen the little devils on lettuce before now but never chard. I would have thought one of your winters would kill them off. Any ideas what you are going to sow to replace them?

  2. they fly, so like aphids, i guess they can show up randomly. it would be good to know at what temps the eggs/pupae die, which i cannot find offhand.

  3. I wonder if you could spray them with a very diluted soapy water solution-would that dissuade the little jerks? It works for aphids.

  4. Leaf miners attack Swiss chard, beets, and spinach, so if any are growing nearby and they're infected, you'll have them too. The adult is a small 5-mm iridescent fly that likes to land on large-leafed plants like squash, but doesn't attack them. Eggs are tiny white slivers laid in a row on the undersides of leaves. After larvae are done destroying the leaves, they drop out and pupate in the soil. You can kill the eggs with soap sprays, but I just smear the eggs across the underside of the leaves with my finger. If you get the first wave of eggs in the spring, you'll have fewer problems the rest of the year. You can see photos of these pests at


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