Decagon -- Weird. We used to see a regular plague of whitefly up here in Ventura Co., but it came under control when the local farmers reduced their use of broad-spectrum pesticides.

Can you get some hummingbirds into the garden?
They looooooove whitefly!

JEri

pyrethrine is a natural broad-spectrum killer for aphids, thrips, whitefly & co. It is contained naturally in certain plant species, as a natural defense, and in the EU it's use is allowed even in biological (i.e no poison) agriculture, where "no-chemicals" is a must.

If it does not rain, it's effect lasts about 10-14 days.

The more broad-spectrum pesticides you use, the more whitefly you will have.
This is a lesson everyone in our still-agricultural area had to learn.
NOW most farmers surround their fields with "insectaries": Clumps of grasses and flowers that attract insects of all sorts away from the crops.

Also, hummingbirds (as I said above) are death to whitefly. They can be your greatest asset -- but not in a garden that's sprayed.

Jeri

Do insecticidal soap sprays work against whiteflies? It seems to me they ought to, but then again I realize if you have tons of them in your area and they're coming in from someone else's yard or field I realize your soap spray may not help much.

Thank you all for the good advice!

Jeri: Weird - I know...I thought white fly was history around here too. I hope it's not a sign that a plague is on the way again. We used to have lots of hummingbirds, but our neighbors started cutting our trees (without our permission...another story). Now, I rarely see a hummingbird, or any of the other birds that used to nest here each year. Maybe that's why the white fly is back?

What types of plants and grasses attract white fly AWAY from my garden? I'm willing to try anything.

Scardan and York Rose: If I can't tempt more hummingbirds to return or get it under control by spraying with water, I just might try very localized applications of pyrethrine...like spraying only directly on effected leaves when the white flies are resting to see if that stops them. I hesitate to spray any other way because I have lots of beneficial insects and have never used sprays of any kind on my plants, herbs, and veggies.

Keep on hesitating to spray. :-)
The problem with spraying whitefly is that the little devils don't live long to begin with.
Mostly, you just kill beneficials. :-(

Good point about your trees.
To make sure we have lots of hummers, we put out several feeders.
Keep the sugar content of the nectar at the low end, and the hummers will be encouraged to
"hunt," -- IOW, eat whitefly and aphids.

I've never really investigated what's in the plantings of "insectaries," but I know there
are grasses, and some flowers.

Jeri

*slaps self on forehead*

Feeder...duh! I have a couple that I'll put up again tomorrow morning. That should entice the hummingbirds back. It's the perfect time of year now because they're getting ready to nest.

Thank you for reminding me about the feeders Jeri!!! I can't believe I forgot I had them.

Whiteflies won't be anywhere near as easy to knock off with a jet of water as aphids are. The adults will just leave for a few minutes and then return, while the immatures (that actually do most of the damage) are mostly flat and won't be dislodged by the water cascading over them. It was because of the immatures that I thought of insecticidal soap. When it works it does so because the soap interferes with the wax coating on the whiteflies and prevents it from protecting their bodies from dehydrating.

Unfortunately I'm not certain if those soaps have a documented record of successfully controlling whiteflies. I know they work with aphids and some other insects in this same insect suborder. (Whiteflies and aphids are in the same insect suborder, one that also includes leaf hoppers, cicadas, spittlebugs, and all the scale insects, including mealybugs.)

For a year or so, in one of the big local outbreaks, we had whitefly laying eggs underneath the leaves of plumeria, begonias, and brugmansia. They really seemed to love the plumerias.
I took to looking for them every couple of days, and I would wipe them away with my fingers.
That seemed to do more for reducing the population in our garden than anything else we did (other than hummingbirds) -- so you might want to try to see what plants they are colonizing, and deal with them at that stage.
(They do not seem to colonize roses, in my experience.)

Jeri

We used to have white fly problems but word was the cotton fields were being sprayed with a different formula. I think it might be imidacloprid (Merit, Bayer). Shortly thereafter humans moved in by leaps and bounds, bulldozed the areas and coated them in stucco and cement, pushing the cotton fields and whiteflies further out. I used to hang yellow sticky paper in my rosebeds. I limited/quit using chemicals in my garden a few years ago. No whiteflies but I encourage small birds, hummers and beneficials with nectar feeders, bird baths and spraying the leaves with water a couple times a week. Cool down the rose garden on a hot day and it's akin to opening a bug buffet.