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I have several perilla/shiso plants grown from a batch of seeds. Right now all of them look spotty and yellowish rather than deep green like those you get from stores. Is this a disease or are they missing nutrients / particular minerals? enter image description here

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    can you add a picture of the underside of the leaf in case there are bugs? – kevinsky Jan 1 at 20:48
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    Thanks Kevinsky. At first I couldn’t see any but I guess I wasn’t looking closely. I can confirm I see these tiny red spots on the back of almost all the leaves. Are they bug eggs? – Aobo Song Jan 21 at 11:52
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Perilla is an annual herb and can be subject to rust which shows as rust coloured spots.

As the spots on the leaves in the picture are light coloured it looks like aphids or spider mites which suck sap.

Spider mites are the size of a grain of salt and cluster on the undersides of the leaves. You may need a magnifying glass to see them. They make a web when populations get large and can spread to other plants.

Aphids are much larger and come in a variety of colours.

Both can be controlled with at least three applications of soap and water at five to six day intervals applied at a ratio of 25 ml of dish soap per litre of water.

As these plants are grown to be eaten and they are annual seedlings I recommend either planting them outside and hoping for the best or throwing them out. Most seedlings are too delicate for the soap and water method of control.

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  • Thank you so much! I think you are right, they look like spider mites from your description. Looks like I have to let all of them go. Do I need to treat the soil with soap water before planting a new batch? – Aobo Song Jan 22 at 4:36
  • @AoboSong you can bake the soil at about 200 deg c for 20 minutes to sterilize it. If that is not possible then consider using that soil in the garden. Seedlings need the best conditions to prosper – kevinsky Jan 22 at 12:46

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