4 minute read
Highlighting biosecurity risks for fresh vegetable growers
HIGHLIGHTING BIOSECURITY RISKS
FOR FRESH VEGETABLE GROWERS
Words by Lisa Wong : Research & Technical Specialist, Market Access Solutionz Ltd
Figure 1: Fall armyworm larvae and damage to a corn ear, Image source: University of Georgia, Bugwood.org. Creative Commons 3.0
Monitoring the activity of emerging pests and diseases around the globe helps growers prepare for and manage biosecurity risks that could threaten vegetable production in New Zealand. New pests and diseases are continually emerging and causing damaging effects on many crops and could be a risk to New Zealand.
Vegetables New Zealand regularly monitors several pests and diseases because they have a greater potential to enter, spread, and become established in New Zealand on vegetable crops – these are termed ‘priority pests’. Many of Vegetables New Zealand’s priority pests are common to other vegetable product groups, such as fall armyworm (Spodoptera frugiperda), vegetable leafminers (Liriomyza spp.), and chilli thrips (Scirtothrips dorsalis), while other exotic pests and diseases are important to only one or two vegetable product groups (see VR&I article in this issue), for example, Cucumber green mottle mosaic virus (CGMMV).
Cucumber green mottle mosaic virus is a Vegetables New Zealand priority pest
CGMMV is a pathogen that affects cucurbit host crops such as watermelon, honeydew melon, rock melon, cucumber, zucchini, scallopini and pumpkin, and is one of Vegetable New Zealand’s priority pests. It is also important for the New Zealand Buttercup Squash Council. CGMMV was first described in England in 1935. Since its discovery it has spread across Europe, Asia, and North America. Its spread accelerated from the mid-1980s, and by 2016 it had spread to North America and arrived in Australia. If CGMMV arrived in New Zealand, it would have a major impact on the local production of cucurbit crops. There is no known cure for CGMMV.
Symptoms of CGMMV infection are light green mottling and mosaic patterns on the leaves, blistering and distortion (Figure 2). It can also cause plants to be stunted, and importantly, it can cause severe crop losses. New Zealand imports a large quantity of cucurbits from Australia, especially watermelons, melons, and zucchinis. In December 2019, CGMMV was intercepted on a consignment of fresh watermelons being imported from Queensland. The consignment was suspended, and Australian authorities asked to investigate the situation. After Australian authorities put in place measures to satisfy the Ministry for Primary Industries that future exports of cucurbits would be free of the virus, importing cucurbits from Queensland was reinstated in March 2021. Fresh cucurbit imports from Australia are now required to be sourced from an accredited property that is a ‘pest-free place of production’. The Import Health Standard for Fresh Produce has also been amended to reflect the requirement for a ‘pest-free place of production’.
Figure 2: Typical CGMMV symptoms on greenhouse cucumber plants, Image source: http://www.agriculture.alberta.ca
Vegetables New Zealand has been closely monitoring CGMMV since its arrival in Australia. This involves checking notifications from national and international industry and plant protection organisations, and searching the international literature and databases. Close monitoring means that action can be taken quickly when a biosecurity risk increases so that the vegetable industry can be protected.
Fall armyworm update
In the year since its arrival on the Torres Strait Islands and northern Queensland in February 2020, the fall armyworm has become established in Australia. A first report has also emerged from New Caledonia in January 2021. Fall armyworm can travel long distances blown by strong winds. The impact of fall armyworm is not only being experienced in Australia but globally. Since its spread to Africa, the Indian subcontinent and China over the last four to five years, considerable efforts are being channelled into searching for ways to reduce its impact using methods such as chemical or biological control, and finding out which characteristics make it such an invasive and destructive pest. Many Australian grower organisations have developed resources and presented webinars to support growers and increase their awareness of fall armyworm.
Learn more about CGMMV: https://www.
youtube.com watch?v=PNugs5NvcI
Learn more about Fall armyworm from Ausveg (https://
ausveg.com.au/articles/fact-sheets-fall-armyworm-2/)
or watch the ABC’s short segment on fall armyworm
https://www.abc.net.au/landline/hungry-caterpillar:fall-armyworm-hits-australian/12122370
Maintaining an awareness of priority pests
Through the ‘Monitoring Biosecurity Risks’ project supported by the Vegetable Research & innovation Board and by monitoring its priority pests, Vegetables New Zealand is able to maintain an awareness of the risks posed globally by new and emerging pests and diseases. Vegetables New Zealand has factsheets so that growers can keep up-to-date on which exotic pests and diseases they need to keep an eye out for when scouting crops. Maintaining awareness of these high risk new and emerging pests and diseases is important so that New Zealand growers remain prepared for potential incursions. The Vegetable Growers On-Farm Biosecurity Manual should be used to assist growers in planning biosecurity management. This manual has been sent out to most growers, and if you need a copy, please contact Vegetables New Zealand.
For more information please go to the Vegetables New Zealand website:
