Please help ID tiny white specks on all plants in greenhouse
I have tomato, pepper, eggplant, and herb seedlings in my greenhouse, and I just noticed what seem to be tiny white specks all over the plants. No group of plants is more affected/less affected than the others. Absolutely every variety, from tomatoes to nasturtium to oregano to basil, suddenly have these white specks.
It seems this happened within just a few days, and there are thousands, if not millions of tiny, dust-like white specks evenly spaced on the plants throughout the greenhouse. The leaves show no signs of insect damage, and these white specs can be rubbed off with my finger. Under 30X magnification, they look white, oval, fairly evenly sized, and many of them, but not all, seem to have a dark line across the midline of the oval. Most of these specks are evenly spaced across the top surface of the plants, but there are some on the undersides of the leaves also. Occassionally, there is a cluster of 20 or so specks (in an oval cluster, not in a ring or line), but mostly they are single specks evenly spaced apart about 5mm or so across the entire surface of all of the plants. It looks as if someone sprayed dust all over, there are so many. I regularly examine the plants carefully but I've found no evidence of adult or juvenile insects. The greenhouse is open during the day, and insects can come and go. I use only organic methods.
I would greatly appreciate any help or ideas. I cannot imagine an insect that can lay eggs at the rate these must have been layed if they are eggs. It looks almost like dust that fell on the plants, but careful inspection seems to indicate there are specks on lower, covered leaves as well as top leaves. Newer foliage does not seem to be more/less affected than older leaves.
We have had very windy days the past few days, and I wonder if this could be pollen and the clusters are where there was a droplet of water, or if this is the beginning of some gigantic insect infestation.
Do you think this is insect eggs or maybe pollen or possibly fungus spores? I have researched online and found no eggs that look similarly. Thanks so much for your help.