Hi I was sitting outside late this afternoon and every 10 minutes or so a white tuft of something would float past. Some were a meter long and some seemed to improbably be gaining altitude. One finally landed nearby and it was the consistency of cotton candy; like spider web but not sticky.

Anyone know what these are?

they are pollens

Or webs. Some spiders parachute away after hatching.

They come every year. Not sure what they are. One year they carried a fungus and every plant and tree they came in contact with became infected with the fungus and we lost a lot of our garden. Took about 6 months for the trees to have foliage again. We looked at a new moobaan in Mae Jo that same year. They had only finished the landscaping about a week before the 'cotton candy' things came. The entire moobaan was infected with the fungus and everything died just before the opening!

I can't be 100% sure it's from them but it seems I get a cough right around the time they come.

Jeepers creepers. It sounds like the stuff of nightmares. 'The day the cotton candy things came......'

Triffid pollen.

'cue scary music'

Aliens

Ive just looked on some plants around the section, and I have also seen some of this white silky type stuff on various plants. Not huge strands but its very sticky stuff.

Ive narrowed it down to the pest Mealy Bug. Not sure if its what you have but easy to kill the little buggers....otherwise the will kill your plants. They do this by basically sucking the life out of the plant.

But then again maybe this isnt what you have.....