Expert: Mike Mascio - 4/5/2009

Question
Hello, I live in southern California and I recently noticed some weird spots on the leaves of my snapdragons. From the top they're small, light greenish circles (it just looks like small areas where the nutrients has been drained), then underneath the leaf is a small cluster of black spots. It started on one stalk and has now spread to several others. I don't want to use any chemicals if I don't have to. Is this something that will go away on its own or is a fungicide necessary? Thank you for any information.

Answer
I wouldn't take the chance that the disease will go away on its own. The earlier you catch and treat a fungus disease, the better your chances to save the plant.

You can use one of several organic fungicides. These are non-toxic and highly effective against disease. I use one called Soap-Shield, a copper-based fungicide sold by Gardens Alive. Attached is a link to their website. If you click on disease control, you will find several other organic products which also work very well.

http://www.gardensalive.com/product.asp?pn=8066

Good luck, and please write again if I can ever provide assistance.

Regards,

Mike