Help! dahlia wilt & rot with little bugs on tuber!!
Background: First timer here and new dahlia grower!!! I have 2 areas in my yard with dahlia's, both in full sun, but one on the southwest and the other on the south side of the house. I do have rather clayish soil, which I have amended with river loam (sandy stuff), peat moss & perlite several times over the last couple of years in prep for planting flowers and such. I planted bout 15 tubers in April, 12 of which sprouted nicely. Of the 12, only 1 has gotten to a respectable size - it is about 2.5' tall and is setting buds. All the others are under 8" in height. This week and while it was really hot, 6 wilted..2 from 1 area and 4 from the other.
I have been searching online for diseases & pests and and finally dug the poor things up tonight to get a look. I found really odd white lesions (not like mold, but more like tumors) on the stalks under the soil line and of course rotten tubers which were covered with hundreds..thousands.. millions..(not really) of the tiniest white bugs.. reminded me of termites and really grossed me out. I took some pictures and threw the tubers and and dirt with it in the garbage.. lots of the little bugs dropped off though..
I didn't find anything in the diseases that resembled this, and I didn't find any pests that looked like these things. So I don't know if my soil is too bad - or I watered too much - if the tubers started to rot and the bugs came, or if the bugs came and caused the rot? Have any of you encountered anything like this? I am so sad, I was so excited for them to bloom.
Also in the ground - using the same type soil and near the dahlias I have a lilac, honeysuckle, daphne odora, delphinium, lobelia, petunias, some hardy fushias & daffodils - all of which seem fine. Both the daphne and delphinium are very tempermental about wet soil and wilt prone, so I try to be really careful with my watering.
Thank you for your help!