I've had problems with leaf miners on chard off & on... some years severe, some years nothing. Chard grows quickly, and does equally well planted in both cool & warm weather. If this is an intensive egg-laying period (as appears to be the case) it might be best to just destroy those plants, and try again in a few weeks. Chard is one of those veggies I've planted as late as July 4th, and still had a good harvest.

BTW, I've had my best results with chard when it was planted adjacent to cowpeas or yardlong beans. The wasps attracted by the cowpeas seem to act as predators to anything else nearby, most notably aphids. I had virtually no insect damage on chard last year, grown next to climbing cowpeas.

I find that almost nothing I grow is worth the cost of treating---both literally and environmentally. First off, most issues go away completely when a plant is stronger. Your chard may bounce back once it's planted. Stick some seeds between your seedlings in case you lose some. I ordinarily don't believe in removing leaves before they're totally dead---it just makes the pest move farther up the plant---but Flora's comment about the eggs being laid internally got me googling, and removing the leaves is advised in this case, because that's where the eggs are---inside the leaf tissue.

Hi and thank you everyone.

I saw rampant leaf mining on the seedlings. I removed the affected leaves because if the larvae were still in there I did not want them to complete their life cycle.

These are the eggs I took pictures of today. Many a times the leaf mining tunnels start right from the eggs.

There are at least several species of insects that have leaf mining larvae. That is what I understand. I have seen pictures of white eggs exactly as above described for leaf mining insects.

I dont think I have been negligent. It is hard to describe how fast things are going from zero to decimation.

Well I hope to get my whole lot of leafy greens in the ground in the next three days. Its good to know that in ground the plants will become far more robust.

@zeedman Zone 5 Wisconsin: Thank you. Good to know starting over in a doable option!

@zeedman Zone 5 Wisconsin: the egg laying is frenzied indeed. This morning I removed all the eggs. Came by less than two hours later to take another look and there were eggs again. Many of them. These bugs are carpet bombing eggs.

I finally got some blue and yellow sticky traps and set them up. Lets see if this affects the egg laying on those leaves in anyway.

Seeing the seedlings now I can see there is a large amount of mining. More than I had imagined. Also the plants are rather large not to be have been transplanted out yet. The later you plant out the more likely they are to bolt prematurely. For future crops, I would either direct sow or plant out at a much younger stage so they can get those tap roots going down and nourishing the plants and not receive such a big growth check. Part of the reason they're getting hit by bugs imo is that they are under stress from still being cramped in those containers. I've always found that chard shrugs off pretty much anything if it's growing lustily.

@floral_uk z.8/9 SW UK: Thank you so much!. I will be getting those guys in the ground now. Hopefully they will pull through. Very useful information for me what you wrote.

Once I started using yellow and blue sticky traps and the egg laying on the chard dropped off within hours. The chard has been completely unharmed and happy since then. How lucky something so simple turned out to be so effective. Catches hundreds of mosquitoes too and no bees.

@zeedman Zone 5 Wisconsin why do you say you have even planted chard till July 4th. I suspect this is very naive but why wouldn't you be able to plant chard by July 4th or even later? If chard is a biennial and you harvest in a cut-and-come-again way what is wrong with planting transplants now or in July? And I understand that chard plants can handle some heat too. Your answer would clarify a lot for me!

thanks!