We use pyrethrins, here, but I would think it's early for whiteflies in London! Is this in a greenhouse?

Hi Tugbrethil,
No, not in a green house and we have barely had any warm weather as yet!
We also have Ladybirds flying around....do they eat Whitefly?
Himself says "Just spray with chemicals".......but I am not that keen on nasty sprays. Any rose I try and grow seems to get Blackspot....could these flies be the precursor...would lots of feeding help...the rose of course not me.

Well, baby Ladybirds will eat baby whiteflies, but they soon outgrow those tiny little morsels, and look for larger prey. If the putative whiteflies aren't flying, however, those little white things may actually be the skins shed by growing aphids, and aphids would easily account for the Ladybirds. Pyrethrins also work on aphids, as does soapy water.

As for blackspot, that's a fungus disease, and it is spread by water splashing off the leaves. The fungus likes the same temperatures as aphids, and often shows up coincidentally. Blackspot fungus is a little harder to control organically than aphids, but wettable sulfur dust is probably worth a try. Also try to keep the leaves from getting wet any more often than they have to be--a lot easier here in the desert! : D

Increasing slightly the amount of potash and magnesium a rose gets will often increase it's disease resistance, as will small amounts of treacle in water--about 2-4 ml per liter, one l per dm of bush diameter--applied monthly.

Hope this helps!

Hi Tugbrethin,
Took a much closer look at these little blighters with my reading glasses on.
You are quite right the white stuff was empty skins and the bugs themselves were folded inside the leaves....odd greenfly though,.. brown and juicy. Put on a plastic glove and wiped them off with my fingers. Although they were probably the sought of little critters that are born pregnant or something, so will for sure take up on your advice on building up the plant with some proper nourishment.

Thanks for your advice.