Western Flower Thrips

Western Flower Thrips (WFT), Frankliniella occidentalis, is one of the most damaging pests to confront the Australian vegetable industry. WFT causes damage by feeding on fruit buds (eg. cucumbers) and spreading Tomato Spotted Wilt Virus (TSWV) in many vegetable crops like lettuce, capsicum, potato and tomato.

This difficult pest often develops resistance to insecticides and is spreading into new growing regions and a wider range of crops, including stone and pome fruits.

Australian vegetable producers have received the key outcomes of this research through a National WFT and TSWV newsletter and a three-year pilot extension project at Virginia. Recommended WFT management strategies have been trialled ‘on-farm’, at Virginia and then transfered to growers through workshops and demonstrations.

Horticulture Australia (previously HRDC) has funded research into the management of WFT and TSWV since 1995 including:

• monitoring the frequency of WFT resistance to commonly used insecticides
  
  
• generating data to support new chemical permit applications
  
  
• developing biological strategies for controlling WFT
  
  
• studying transfer of TSWV from infected plants to new crops
  
  
• surveying common weeds and native vegetation as hosts of WFT and TSWV
  
  
• studying TSWV epidemics in potatoes
  
  
• observing seasonal changes in WFT levels in commercial crops.

Greenhouse and field crops can benefit greatly from area-wide strategies to limit WFT and TSWV levels, in a growing region at critical times. This is achieved by eradicating weeds and old crops before they become pest and virus hosts for other crops.

Most growers gained immediate benefits from recommended practices, but all found they had to adopt a routine program for checking results and comparing with management records. Many of these growers have also substantially reduced their chemical use.