Tales from the Garden: Guard the Chard

Unsightly wilt on Swiss chard

Spring is steadily approaching, which means it’s time to plant new crops in the garden. While most of our prior spring vegetables have either died or remain in hibernation, one plant remained vigilant and bountiful throughout winter: Swiss chard.

But this wasn’t always the case. We initially planted chard last April; however, after the first few weeks, the leaves started to turn yellow and wilt. We had no idea what was going on and thought the plants were being under or overwatered.

I took a photo and sent it to my mother-in-law, who grows chard abundantly in her garden in Ohio. She never experienced this issue and couldn’t help us, which puzzled us further. I did some internet sleuthing to see what else could be the problem was shocked to discover that the culprit was in the photo all along.

I was used to dealing with garden pests before, but not one that was this small. This fly wasn’t an ordinary housefly, but a leaf miner, which is prevalent in the Bay Area. The leaf miner lays its eggs on leaves so that when they hatch, the larvae bury themselves inside the leaves to eat them from the inside, which causes them to turn yellow and wilt. The larvae continue to eat the leaves until they transform into flies, where they then lay new eggs, repeating the lifecycle.

On closer inspection, I could see eggs all over and knew I had to take action to save our chard.

There are really three ways to handle leaf miners. First, you can apply pesticides, which will kill the larvae before they can start damaging the leaves. While this method is quick and easy, it risks harming beneficial insects like bees and ladybugs.

The second tactic is to cover your crops with mesh to prevent flies from getting in and laying eggs. This method is effective but cumbersome and not practical as there are other plants that I wanted access to and didn’t want to deal with taking the cover on and off repeatedly.

This left the remaining third option, which was to simply remove the eggs by brushing them off the leaves. When the eggs hatch on the ground, the larvae can’t climb back up and the leaves remain pest-free.

I spent 10 minutes removing all the eggs from our Chard and celebrated with a cold beer. Mission accomplished, right? But the next day I found even more eggs on the leaves and discovered that the flies wouldn’t give up without a fight. And so for the past year, I’ve spent every morning brushing these cursed eggs off to protect my chard. It’s a hassle and time-consuming, but also not fruitless and our chard began to grow and grow.

One of the great things about winter is that it’s too cold for leaf miners to survive, which means I’ve enjoyed several months of fly free chard without having to do anything. However, the temperature has slowly been climbing, which means it’ll soon be time to guard the chard.