You can use horticultural soap applications, or horticultural oil, or Neem oil. All are considered organic. I've used alcohol solutions to control pest insects on many different kinds of plants, but never tomatoes. Alcohol is actually very safe under most circumstances.

The most essential aspect of whitefly control is that you get your control product on the underside of the leaves where the eggs are laid and the nymphs hang out.

Because of their rapid life cycle Whiteflies develop immunities to many pesticides quite rapidly and that is why none are recommended for control of them. Placing some yellow, or blue or both, sticky traps around will help capture the adults which might limit the larva population, eventually. Spraying an Insecticidal Soap especially on the undersides of plant leaves is the one still really effective control, but not spraying with wide spectrum poisons that will kill off the beneficial insects that will consume these buggers is better.

Here is a link that might be useful: About whitefly

Here are some Organic control ideas for Whiteflies.

Planet Natural Whitefly Control

Whitefly cannot develop a resistance to oils. Oils are a suffocant and they clog the insect's breathing apparatus. Those who are sensitive to soaps can't develop a resistance, either. It's a dessicant.......That's why these are often considered organic, even though the oils (being petroleum based) really aren't in the literal sense.

Traps are a good adjunct to controls, but don't for a second believe they'll do the job. I use traps in my greenhouses, but only to give me an indicator of when the WF are present. I've used neem, it's not a knock down but is also usefull in an integrated pest management situation.

"Whitefly cannot develop a resistance to oils"

Carefull...that has always been the opinion of pest control people and entomologists(sp?). But several years ago I attended a SAF meeting (Society of American Florists) in Florida and Fl. Extension at that time had documented an oil resistance in some type of scale(not sure of pest or plant). It took many years to happen (10+ years is what comes to mind), but it did appear to happen (yes.....a lot of peoples jaws had hit the floor).
I have never looked into follow up work, but SAF meetings usually have some of the top pest/disease people in the USA....not something to dismiss easily.

I surely wish you could remember more particulars about that claim. I'm interested in what type of oil this claim was referring to. Some oils are not used primarily as suffocants, but used to make the foliage distasteful, and some are linked with a certain compound acting as an insect growth regulator.

Saying an insect can develop a resistance to a suffocant is analogous to saying it has in ten years developed a method to stay alive without breathing.

I agree, however, that a person should never say "never" or "always". Let's put it this way, however, when all else fails and you need to kill an insect and still desire a product you can eat after you treat the plant on which it grows, oils and soaps are going to be your best friends.

"Whiteflies develop immunities to many pesticides quite rapidly and that is why none are recommended for control of them".

Really now. Anyone buy that claim?

What is not recommended is relying upon one mode of action ad infinitum.

As for organic controls, rubbing alcohol is used by some, although for me, it seems to attract more than it takes care of. Colored sticky placards...it's fairly well documented that whitefly are attracted to yellow. Neem oil, although if your adherence to organics is due to safety issues, I may rethink that one. Insecticidal soap.

How many plants are we talking about here? a few? A dozen? A greenhouse?

As for your ability to locate predator bugs, this will depend upon two things: how many plants you have to treat and where you are. I have a list of suppliers of beneficial insects for the US, so unless you have so few it's not worth it, I bet we can connect you. If you have that few and that many whiteflies, you may better off starting fresh.

I have a good friend who runs an insect consulting business. If she recommends an insecticide, its because she thinks it's truly the best way to deal with the problem...and it's the last thing she recommends. Most often, it's a recommendation to knock population levels down to manageable levels, other controls from there.

So...how bad is it? Do you have to wear a mask when you get near your plants or else breathe in whitefly?

"Really now. Anyone buy that claim?" Yup. The University of California-Davis, Ohio State University, Purdue, Rutgers, the USDA, The University of Florida are among those I have read that state that whiteflies rapidly develop immunities to pesticides.
People that do recommend spraying lots of pesticides to control whiteflies have not kept up to date on the research that has come down in the last 20 years.

"People that do recommend spraying lots of pesticides to control whiteflies have not kept up to date on the research"

Kimmsr,
I feel you need to re-read the papers about whiteflies, your reading way to much between he lines (or not reading other papers, from the same people, on how to control them). Yes...whiteflies do/can develop resistance to a pesticide quickly,IF the grower is not rotating their mode of action (mentioned above by heptacodium).
If what you state was true, no one would ever have a Poinsettia during the Christmas holidays (they are whitefly MAGNETS) or a field grown tomato from the west coast,etc. etc..
Yes...they are a pain to control(multiple life stages,location on plant, they fly if plant is disturbed,etc.), but knowledge..from the same universities you mention, have shown how to control them well...with hard and soft pesticides...yes, predetors and biologicals also.

" surely wish you could remember more particulars about that claim"

Calliope,

Try contacting Dr. Lance Osborn...Univ. of Florida MREC...considered one of the top entomologists on the east coast among BUG people (of which I am not...but I still deal with them on a day-to-day basis). He started his talk with a question at an Society of American Florists meeting(3-4 years ago in Florida)..."Can a pest develop a resistance to a physical pesticide"..everyone said no...he related otherwise.
Paraffinic oils are probably what is used in florida, not Neem oil(the Insect Growth Regulator or distasteful spray you mentioned)...but worth clarifying with him.

Thanks for the info schmoo.