Leaf miners. Fly lays eggs on leaves, maggots hatch and excavate tunnels thru the leaves' interior causing the damage you see. They love chard and beet leaves, as well as spinach. Although I can identify them, I don't know how to prevent them, other than not growing what they like when they like it. With my beets, I've had some success with cutting out the damaged leaf portions when they're small, taking the maggots along.

I wish I could tell you what it is or what causes it..sorry, I dont know...But I do grow chard and whenever I have seen leaves doing that (or yellowing) I simply cut them off, throw them away and the plant marches on, without a hitch.

Of course if it's happening on a larger scale and not just a leaf here and there, then of course you'll probably need to do something more pre-emptive. In which case I'm sure someone more knowledgeable on recognizing actual names of conditions etc. will chime in and help you.

so far in all the years I've grown it I've never had to spray my chard or treat it in any way...so I guess if that simple solution works, that would be the best thing to do.

I grew chard last year and had this problem. I assumed it was leaf miner. All I did was stay on top of cutting the yucky leaves off for a couple of weeks, after that all new growth was fine.

We harvested tons of chard from a 3x6 foot section.

thanks for the info! i'll just keep cutting off the bad leaves. they're pretty prolific though, hopefully this will get rid of them.

ed

I was talking at my local garden shop about the leaf miners in chard. They said leaf miners here (in Oregon) are the worst they can remember. My chard is being eaten alive, and they are spreading to my beets and spinach, to a lesser degree. An interesting thing to do is to hold-up a damaged leaf to look through it in daylight. You can actually see the bug in there, if it hasn't left yet.

I was at first thinking of spraying, but instead I got some light summer-weight row cover that I'll drape over the affected plants... We'll see how that works.

I'm not much help, but just wanted to say "HI" to another Eugenian! I actually live in Elmira, but work in West Eugene.

ON Topic: My chard doesn't seem to have been affected, at least not yet! Beets are only about 3-4" tall, nothing yet.
And for some reason, I can't grow spinach at all. Just will not germinate for me. Several years running. Indoors, outdoors, doesn't seem to matter.....Spinach doesn't like me.

Deanna

Yep, those are leaf miner trails. If you flip the leaf over, you will see teeny, tiny white patches of eggs. Be sure to check the leaves that don't show any damage yet too. They can be wiped off gently with a wet paper towel. I was just about ready to rip the spinach, chard, and beets out, because there is so much damage, but maybe I'll follow Jenangelcat's advice of just continuing to remove the bad leaves until the damage stops.

Bonnie

Deanna: I lived off of Horn Rd in Elmira for a few years when I was a kid, I have fond memories of walking to the store at the end of the road (I believe it has since closed) to buy candy...often. Hi!

I removed the bad leaves today, hopefully the leaf miner invasion will cease soon. They're killing off all the good leaves before I can get a chance to eat them, and I love chard!

What a small (but great big) world, huh?
Deanna