Question
You had someone ask why her petunias were all drying up and dying, anyone come up with anything? I have planted at least 25 containers on my deck with a mix of plants and the petunias in every container have died. They look fine for a few days and suddenly dry up and die. None of the other plants are effected. I have a couple that I replaced only to have holes ate in the leaves, flowers chewed, and black dots everywhere. My geraniums look the same. I've sprayed with pyrethrin and a homemade insecticidal soap with no luck.

Answer
Nanc,
The holes, chewed flowers and black dots are from a larvae of some sort - usually a green "worm" that is eating the plant. The black dots are the larvae poop. Spray with any product containing Spinosad to solve this problem.

If the petunias turned yellow before they dried up, they were probably too wet and got crown or root rot. If they turned brown without being yellow and wilting first, then it could be fertilizer burn. Might the containers have been fertilized when the soil was dry?  Fertilizing with a synthetic fertilizer that is slightly too strong when a plant is dry can cause this and some plants are more sensitive to burn than others. I suppose it's also possible that the larvae ate around the petunia stems near the bottom of the plants and this girddled the plants, causing them not to be able to take up water.

I hope this helps!
C.L.