Something is harming my dahlia buds

Hello this dahlia is new this year. It bloomed red with a yellow center. Now however all the buds turn into dried petals sticking out and no flowers form. I have never seen this problem before.

 

This is not my area of expertise at all, so I hope someone else with experience will step in.

In the meantime, read through here:

Wilting Dahlias

 

There are no aphids, no powder mildew, but when I picked up the pot to lower it down so I could look at it more properly, a small dark, rather flat insect scuttled away, paused, then as I reached for my camera, disappeared. The insect is not familiar to me.
The dahlia was planted with the surface of the soil at least an inch below the top of the pot. I carefully removed the dahlia from the pot, put in more soil and replanted it. During this time I saw no evidence of insects. Some of the bottom leaves look paler in areas, though this is not widespread. I put the pot in a different area on the railing and watered it in, so water flowed out the bottom. I was watering less, more frequently (to avoid the water coming out the bottom), but I will go back to watering less frequently and a greater amount.

 

My concern is that it might be a virus (that seemed to be the worst-case scenario in the above article). But, like I said, no experience on my part.

 

I looked at the tomato mosaic virus picture at Plant viruses/RHS Gardening and the leaves look similar to the leaves I saw on the bottom of the plant. I had cut off the effected buds and thrown them into the city green bin. Is this a problem? Should I bag the dahlia and throw it in the garbage rather than the green bin? Should the soil be discarded?

I had this dahlia since 2015, but overwintered it in it's pot in a shed, no moisture, and kept above freezing. I have another dahlia bought the same year in a larger pot and overwintered the same, which has not been effected (yet). The effected dahlia being in a smaller pot may have been heat stressed last summer due to being in a smaller pot in full sun.

 

Rats got into the shed last winter. I wonder if they brought the virus, because nothing else seems to effected, and I have never had it here before, and no one smokes here. So I guess maybe the rats picked it up on their feet somewhere or something...