|I have 4 outdoor window boxes, and this spring as I bought new annuals, zinnias, petunias, geraniums, an infestation of tiny tiny black things attacked and within a few hours, had overrun the tiny plants - tiny black spots on leaves, stems, all over, killing them. (It didn't attack the herbs or snapdragons.) But it was insanely rapid. I had the same, if less virulent problem last year, but since my coleus did fine in the same window boxes, then my bulbs came up fine, I thought the insects gone. Apparently not. What are they and what do I do? A most discouraged new gardner.|
|Unfortunately, based on your description I am unable to identify the pest, although it might be flea beetle. I would suggest you contact your county extension for a definite identification of the pest and their suggestions for how to control them.
You might also consider removing all of the existing soil in the boxes at the end of the season next fall and then replacing all of the soil next spring. This might eliminate the overwintering opportunity and reduce chances of their presence the next year.