Tap the leaves and, as a cloud of flies up, suck them up with
a small car vacuum cleaner - take care! or you'll damage your tender little
plants.
Whiteflies are also attracted to yellow paper, so you could try
hanging strips of sticky yellow card which the whitefly stick to - these are
available commercially and if you think you have whitefly will become covered
surprisingly quickly. They also serve as a good early warning for if you suspect
that you will get whitefly.
Avoiding whitefly on tomatoes without the use of chemicals.
Plant French Marigolds (Tagetes) between your tomato plants to keep those pesky
Whitefly away. It's not that the Whitefly particularly don't like these marigolds,
it's because the pungent smell from the marigolds masks the nice smell of the
tomatoes that usually attract the Whitefly.
Another option is to go for biological control. Biological
control of a pest relies on introducing a predator species so "fighting nature
with nature", if chosen carefully, the predator will stop damage to your plants
without damaging the environment. Such biological controls are safe for the
user, children and pets. They will not harm other beneficial garden insects
and are biodegradable.
The biological control for whitefly is the parasitic
wasp, Encarsia formosa. These minute little wasp's parasitise the whitefly
pupae. Encarsia is only suitable for glasshouses and conservatories.
Encarsia needs a 24 hour average temperature in the glasshouse of at
least 17°C
