Brown Spots on Chard Leaves

Asked May 4, 2013, 9:59 AM EDT

Hello, I have a question for someone in the Master Gardener Program: I planted a raised bed vegetable box about a month ago, which includes Swiss Chard. It has been doing very well, but in the last few days it's been developing some brown, thin spots in the middle of the leaves. Is this weather related or disease related? Is there a solution? Thanks so much! Sara Hull

Clackamas County Oregon fruits and vegetables

1 Response


Good day, and thank you for using Ask an Expert.

From the sounds of your description, several possibilities come to mind. Of them, I suspect that leafminers may be active.

Leafminers are small flies which lay their eggs on the undersides of the leaves. After the larvae (youngsters) hatch, they burrow into the leaf and feed between the upper and lower leaf surfaces. One burrowing pattern is a squiggly line, the other a large, irregular edged blotch. With the blotch type, you will be able to separate the two layers of the leaf. When you tear the layers apart, you might find some of the worm-like youngster still feeding before they drop to the soil.

We can easily clear this up if you attach several images when you respond to me. Preferred are an image of the plant(s) overall, and another of a damaged leaf. After I receive your images, we’ll be able to discuss what you can do to resolve the problem.

I look forward to receiving your pictures.