Whitefly infestations tend to be more problematic indoors, for example, in a glasshouse setting. In most cases, whitefly is spread to glasshouses via new plants. Check or quarantine plants for any nymphs prior to putting it in the greenhouse. Planting rhubarb in greenhouses is thought to deter whitefly too.
Whitefly eggs can be found underneath the leaves of plants, so these areas should be inspected regularly.
Remove Whitefly eggs with a cloth and soapy water or rubbing alcohol.
Any spacing between plants should be kept clear of weeds and debris. The use of netting can sometimes improve protection.
For lighter infestations, plants can be gently hosed down to remove whitefly and eggs.
Ant traps placed near affected plants will aid controlling any secondary infestations.
Whitefly is drawn to the colour yellow. You can use yellow cards or sticky traps to attract whitefly and monitor the infestation level.
Insecticidal soaps and neem oil can give some control over whitefly, and it's less harmful to the environment when compared with pesticides. Bottle labels should be read carefully. Oils can react badly with high temperatures and burn the surfaces of plants.
Beneficial garden creatures such as beetles, wasps, lacewings and spiders will eat whiteflies. These can be attracted into the garden using a few simple tricks, such as incorporating insect hotels or by letting parts of the garden grow a little wild.