Dying Cosmos

[LexLucre]

I grew some mixed cosmos seed in pots this year. A month or so back two of the plants suddenly died, all of their foliage went brown, the stems went brown and then it was game over. They'd been treated the same and were right next to the other pots.

A month later and it looks like the other plants are going the same way. The leaves look they've gone rusty.

Any idea whats killing them off, some sort of bacterial thing?

[Mitzi]

Have you emptied the pots and checked the roots? Vine weevil grubs or something else eating the roots can cause sudden death. They probably wouldn't cause rusty leaves, though.