spinach leafs have brown like patches

Asked May 19, 2014, 10:36 PM EDT

hello! i was told that my spinach in my garden has a common spinach leaf disease or something going on that is not unusual for spinach here in the valley. many of the leaves have brown patches on them rendering them inedible. it almost looks like i got fertilizer on the leaves and they got wet and left brown spots. Unfortunately i did not fertilize them. Is there a spray i should b using or what might you recommend i do to prevent this from continuing? thanks so much in advance for your help.

Marion County Oregon vegetables spinach horticulture

4 Responses

There are a couple of possibilities. One is downy mildew, characterized by gray/brown fuzzy patches on the underside of the leaves and yellow blotches on the upper side. Leaf spots (caused by another fungus) are small and are brown and can be numerous. There also is a spinach leaf miner that lays her eggs on the leaf surface and the larva burrow between the upper and lower surface of the leaf and eat all the juicy bits out. The injury is brown and somewhat papery feeling. Let me know which one fits the situation the best and then we can communicate about what you can do. Chip

Thanks Chip for you reply and help. I think it may be the leaf spot that you mention. I have attached a photo. It could be the miner as the injury is brown and papery feeling but i do not see any bugs or eggs.... I clipped off most of the bad leaves and it seems to have slowed down but at least a quarter of my spinach leaves have this.

It is the leaf miner. You have to look carefully to either see the tiny larva in between the leaf surfaces or to see their droppings in the " in between" space after they have left. Plants can be protected by row covers over the leaves to keep the fly from laying her eggs and/or an organic insecticide "spinosad" (this is the active ingredient) sold under several trade names in the home garden market. The leaf miner can also attack beet and Swiss chard leaves. Chip

Thanks a bunch Chip. I went and got some "spinosad" and will apply today. I also just posted an issue I am having with my tomato plants. Not sure if its the same thing but we will see what your team says! Again, thank you very much.