Whitefly on cabbages - Do they do any damage?

[SarzWix]

Went down to the lottie yesterday, and lifted the enviromesh off the brassica bed to do some weeding, only to be greeted by a cloud of whitefly coming up from the savoys. Is this something I need to worry about? Or will the imminent frosts finish them off before damage is done? I can't really leave the cover off yet - still seeing cabbage whites floating around this afternoon - so they have a bit of a protected environment at the mo. I'd rather not spray them unless necessary to keep veg healthy!

[Snadger]

Get a portable hoover, as used for cleaning cars and suck em up while shaking the plants! Never tried it but I've been told it works!

[SarzWix]

Hmmmm, I've got one of those...
Read somewhere about waving one of those yellow sticky card things around above them and they're supposed to fly up and get stuck. Do they actually do any damage though to the cabbages though?

[Paulottie]

They suck the sap and do weaken the plant. They seem really bad this year. Maigolds planted between your toms, strawberries and brassicas helps through the season. Yellow cards not that selective and are really for greenhouse use. There is, a commercially available, wasp called Encarsia formosa That lays its eggs inside those of the white fly but again its more for polytunnel/glashouse use

[Snadger]

They suck the sap and do weaken the plant. They seem really bad this year. Maigolds planted between your toms, strawberries and brassicas helps through the season. Yellow cards not that selective and are really for greenhouse use. There is, a commercially available, wasp called Encarsia formosa That lays its eggs inside those of the white fly but again its more for polytunnel/glashouse use

Do pests just not like the smell of Marigolds and Tagetes or do they just use them as a host plant instead?
I have them interspersed everywhere and have very few pest problems but they don't seem to attack the Tagetes/Marigolds either!

[Paulottie]

No, you were right first, It is the smell but in addition, they are very attractive to hoverflies that arrive to eat aphids too....two for the price of one hey.