Chris & Jessie Davis said:

Could someone please help me by telling me how to get rid of these small
white fly's on the undersides of my tomatos leaves as well as several
outdoor ornamental plants. Thanks for any help you might have.

Vacuum them off the top of the plants; put the vacuum bag in the freezer to kill the
flies.

Wash the young crawlers off with a strong spray of water. Do it in the morning,
at least three times, every other day. You could also try spraying a mix of soap
and seaweed to kill them.

Yellow stick traps placed in between the plants will catch them (but may also
catch beneficial insects).

There is a predatory insect that can be purchased for whitefly control in the
greenhouse, _Encarsia formosa_.

Plants that are short of phosphorous are said to be particularly prone to attract
whitefly. Plants that are well-supplied with magnesium are less attractive.

--
Pat in Plymouth MI

Any technology distinguishable from magic is insufficiently advanced.
(attributed to Don Marti)