My French bean plants have diseased leaves as shown below: enter image description here

What can be causing this? The beans themselves are relatively plentiful.

Location: India. Weather In May-June: Hot! > 95F days.

The bottom side of the leaves have small white flying insects as shown below: enter image description here

1 Answer 1


You have a little zoo under those leaves. The flying white insects are white fly. The long curly lines on the leaf are leaf miners and I think you have spider mite damage too judging by the stippling of yellow areas where the plant juices have been removed by insect activity.

You could do nothing as you only want the beans to harvest or spray a mixture of dish soap and water on the underside of the leaves two or three times at four to five day intervals.

The leaf miners cannot be treated with soap but they are not significant.

Edit: White fly is the most likely pest that fits the description but they could be something else. Either way spraying with soap and water will control them until harvest time.

  • Wow, leaf miners, and I thought these trails were left from snails in my garden! That explains why I couldn't find the little culprits...
    – nettle
    Jun 26, 2012 at 19:32
  • @kevinsky - Thanks. But are you sure those are white flies? Becuase these look a lot thinner and elongated than other white flies.
    – gatul
    Jun 27, 2012 at 6:35

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