Extending the message on virus and bacterial diseases in vegetables

Key to implementing useful and strategic management strategies to control diseases in vegetable crops is the correct identification of the problem and also avoiding new problems entering crops.

As part of the Horticulture Innovation Australia funded project ‘Area Wide Management of virus and bacterial diseases’ (VG16086), the project team lead by DPIRD’s Dr Craig Webster have started grower and industry workshops in vegetable growing areas across WA. These workshops are being run in collaboration with vegetablesWA and AUSVEG with a focus on understanding and implementing biosecurity practices to manage diseases and pests.

At the workshops in Wanneroo, Myalup, Manjimup and Albany, Callum Fletcher (AUSVEG) explained about biosecurity threats to the horticultural industry and biosecurity measures that farms should be put in place to reduce their risk. He also talked about Tomato potato psyllid (TPP) and how to identify the pest.

Following this Dominie Wright (DPIRD) took participants through practical aspects of on-farm hygiene and disease identification with Craig Webster discussing the use of sticky traps to monitor aphids, thrips and TPP. Early monitoring of insect movement, forewarns growers about the possibility of virus infection in crops.

Craig showed participant’s plant samples infected with common viruses such as cucumber mosaic virus (CMV) and tomato spotted wilt virus (TSWV) and why it is important to identify which virus is present in crops.

Other workshops are planned for Geraldton, Carnarvon and Kununurra later in the year.

Surveys of vegetable crops to identify the major virus and bacterial problems affecting WA vegetable growers across south west of WA have been done on a monthly basis. Tomato spotted wilt virus was found infecting capsicum, eggplant and tomato crops in south west. This virus is spread by thrips, including the western flowers thrips, and cause losses in fruit yield and quality.

Xanthomonas campestris (Black rot) was found in broccoli. This bacterial disease affects many types of brassica crops. It survives in crop debris and in the soil for a long time. Soft rot caused by either Pectobacterium carotovorum or Pantoea agglomerans was also frequently detected in brassica crops. These bacteria also survive in crop debris and in the soil.

The bacteria enter the crops through wounds or natural openings. To reduce the risk of infection it is important to reduce the wetness and the length of time crops are wet.

The WA project team includes DPIRD Plant pathologists (Craig Webster, Dominie Wright, Monica Kehoe and Brenda Coutts), and regional horticulture consultants (Annie van Blommestein from Carnarvon Growers Association (CGA); Rebecca Clarke from Raitech, Kununurra; and Rachel Lancaster from Environmental and Agricultural Testing Services, Bunbury).