A week ago thousands of poppy-seed black round specks appeared on a patch of approximately two square yards on my deck. They had a gritty texture under the shoes, but I figured the rain would wash them out.
However, these eggs (?) started to burst, and left a patch of burgundy red on the slabs of the deck.
Concerned about permanent discoloration, I power-washed the deck a couple of days ago, and now they are back, as seen in the picture. Notice a leaf of a Prunus for size comparison, as well as the red color on the deck.
I don't know if these are insect eggs, or seeds, and whether the discoloration will fade by itself.
