An adult of the silverleaf whitefly. The whitefly is now the target of biocontrol.

Biological control of silverleaf whitefly

Our scientists are researching the biological processes behind invasive pests species and the role of landscapes in implementing effective biocontrol agents.

• 1 August 2010 | Updated 14 October 2011

• Background
• Research
• Biological control and management outcomes

Background

In Australia, and particularly in Queensland, silverleaf whitefly, Bemisia tabaci biotype B, is a pest in vegetable, cotton and grain legume production areas. Globally, it is also a severe pest of these crops and is considered one of the world's top ten invasive arthropods.

Silverleaf whitefly damages crops by feeding, and through the effects of the honeydew it produces, which causes sooty mould to grow on leaves and contaminate fruit produce and cotton lint. It is also a vector of geminiviruses, but these have yet to become a major problem in Australia.

This whitefly is resistant to a wide range of insecticides and management approaches that reduce reliance on insecticides are desirable for long term sustainability.

Research

Our research involves mitigating the impact of B. tabaci biotype B.

This research has a number of focuses, including:

• classical biological control using a parasitoid wasp, Eretmocerus hayati
• role of landscape structure in maximising the effectiveness of E. hayati
• use of the B biotype as a model species for global climate change scenario building in terms of biological invasion impact
• biological processes that influence the capacity for different B. tabaci genetic groups to invade.

Biological control and management outcomes

CSIRO first released the tiny wasp, E. hayati, in Queensland in late 2004. This release offers an opportunity to evaluate the performance of a biological control agent released to manage an exotic invasion using a landscape ecological framework.

Since the releases began the parasitoid has spread as far south as the Sydney Basin, west into the northern New South Wales (NSW) cotton production areas and in Queensland from the NSW border to the Burdekin and as far west as St George, Roma and Emerald - coverage throughout this area is now complete.

In all areas, levels of parasitism are well in excess of those previously recorded from parasitoids already present.

In many areas growers have now modified their insecticide management practices to encourage the parasitoid and production areas such as Bundaberg, Queensland have reported a greatly reduced need to treat for the whitefly.

The research associated with the releases has revealed important clues as to how far and how quickly the parasitoid spreads, information that will be used to develop area wide management strategies that encourage early colonisation by the parasitoid; a process that promises to maximise its effect and further reduce the need to apply insecticides.

Read more CSIRO Entomology Research Projects.