August Pest of the Month: Greenhouse whitefly

Name: Greenhouse whitefly, Trialeurodes vaporariorium

Greenhouse whitefly has a major impact on many nursery stock lines and vegetable crops including cucurbits, potato, tomato, soybean, navy bean, and sunflower. Spread occurs by transport of infested plant material, on people and by wind.

Similar to: Silverleaf whitefly (SLW) but larger and less active.

Description:

Greenhouse whitefly complete a lifecycle in about 5 to 7 weeks. Favours warm weather during summer and autumn, can produce three generations on a sunflower crop cycle with seven generations per year.

Egg: Small, yellowish when laid, darkens to greyish-purple when matured. Laid on underside of leaf, often in circles. Number of eggs laid is dependent on crop type and can withstand freezing temperatures for approximately 2 weeks.

Immatures: Larvae (crawlers) are the only mobile stage. Nymphs are immobile, white to greenish-yellow, can be translucent, flattened and oval in outline, scale-like in appearance. Pupa has a few long hairs and a fringe of very short hairs around upper edge.

Adult: Approximately 1.5 mm long, appear moth-like with white wings held flat and roof-like over the body. Are capable of mating 24 hours after emergence from pupa. Adults are usually found feeding on the underside of young leaves.

Damage: Nymphs and adults suck sap causing plants to wilt, turn yellow, shed leaves and display reduced growth rates if infestations are severe. Discolours lint in cotton. Also produces honeydew, encouraging sooty mould growth, which interferes with photosynthesis and reduces plant vigour. Adult also transmits viruses.

For further information please refer to the pest management plan on whiteflies  or to the industry Pest ID Tool at www.pestid.com.au.

Note that the Pest ID tool is now available with free access to industry.

An initiative of the Nursery Levy funded National Nursery Industry Biosecurity Program (NY15004) and ‘Building the resilience and on-farm biosecurity capacity of the Australian production nursery industry’ Project (NY15002).