Whitefly - Symptoms and how to Control them!

What is Whitefly?

Whitefly is a sap-sucking insect which is about 2mm long and when adult has white wings. It is most  often found in crops and plants grown in a glasshouse or conservatory. It is a pest that can be found on the underside of plant foliage and when disturbed will fly upwards away from the plant.

Symptoms

Common name: Greenhouse whitefly, cabbage whitefly and other plant named species
Scientific name: Trialeurodes vaporariorum, Aleurodes brassicae
Plants affected: Many although soft leaves plants are most susceptible.
Main symptoms: leaf yellowing, sticky upper-surface of leaves and possible black sooty mould from sticky honeydew produced by larval stages.
Most active: all year round at 10C up to 35C, if temperature is lower they simply slow their rate of development.

Control

Non-chemical

The widely used parasitoid wasp Encarsia formosa is very good at small populations but will struggle with large populations, the wasp lays its egg into the third stage larva, anything older or younger cannot be killed.

Chemical

Physically acting contact sprays such as SB Invigorator for adults integrated with biological for larval stages.

Written by: Neil Helyer, IPM Specialist, Fargro Ltd.