Rusty color spots on the long bean plant leaves

Bean    NYC

Can anyone tell me what is causing the rusty brown color spots on the long bean plant? I tried cleaning it but it doesn't rub off. I see tiny black spots on the bottom side too. How can I get rid if it? Should I remove all of the affected leaves?

Posted by: michelle (5 points) michelle
Posted: July 24, 2014


Could it be thrips? Some of the white spots on the top leaves are suspicious of thrip feeding. And the mention of tiny black spots on the underside may point toward insect droppings. You may need a magnifying glass to see them, but I would look for thrips on the underside of the leaves.
If they do turn out to be the problem, a Google search for thrip control is a good place to find control options. A comprehensive overview is available at http://www.ipm.ucdavis.edu/PMG/PESTNO.... I often try a water spray as a first treatment (not too forceful). Insecticidal soaps or neem oil are popular options.

Posted by: Charlie B. (2 points) Charlie B.
Posted: July 25, 2014

michelle commented,
Thanks for your help. I added an underside leaf picture. Some parts are also brownish, but they don't rub off. Towards the stem there are tiny black spots that can be removed. I'll try the insecticide soap. I just don't want to clip off all the discolored leaves. And the article you attached said clipping problem leaves won't help.
almost 6 years ago.

You need to log in if you'd like to add an answer or comment.