Cucumber green mottle mosaic virus
Have you seen Cucumber green mottle mosaic virus (CGMMV) symptoms? CGMMV is a serious disease of plants in the cucurbit family (such as melons and cucumbers) and all suspected cases should be reported immediately.
Be on the lookout for Cucumber green mottle mosaic virus and report it to Biosecurity Queensland.
Call Biosecurity Queensland on 13 25 23.
Cucumber green mottle mosaic virus (CGMMV) is known to be present in the Northern Territory and Western Australia and has been recently confirmed in Bundaberg, Queensland.
Although CGMMV is not considered to be established in Queensland the disease has previously been detected in commercially grown watermelons at a property west of Townsville in 2015. Biosecurity Queensland is working with the affected property owner to contain the disease and to eradicate CGMMV.
Biosecurity Queensland is responding to the detection in Bundaberg by placing biosecurity restrictions on the infested properties, completing surveillance to determine how widespread the disease is, and working with affected growers to develop an appropriate eradication strategy.
Biosecurity Queensland is also undertaking ongoing surveillance across Queensland to ensure CGMMV has not spread to other parts of the state.
CGMMV is a virus affecting cucurbits.
CGMMV does not pose any risk to human health.
External symptoms of CGMMV in watermelon include mosaic-like mottling of leaves, necrotic lesions on the stem and the malformation of fruit. Internal symptoms of CGMMV are internal rotting with yellowing or dirty red discolouration.
All cucurbit growers should be aware of CGMMV, and ensure they have good biosecurity practices in place to prevent the introduction of disease to their properties.
The melon industry biosecurity plan (PDF, 1.2MB) provides a mechanism for industry, governments and stakeholders to better prepare for and respond to, incursions of pests that could have significant impacts on the melon industry.
For more information about the CGMMV National Management Plan and other biosecurity resources for growers visit Ausveg.
There are a several strains of CGMMV. Some strains of the virus affect cucumbers, whereas others do not. The strain of CGMMV detected in the Northern Territory, Western Australia and Queensland has a high level of homology to Indian strains of the virus that infects watermelons and bottle gourd.
Virus particles that are rigid, rod-shaped and 300 x 18nm in size.
In September 2014, Cucumber green mottle mosaic virus (CGMMV) was reported for the first time in Australia from melon crops in the Northern Territory. CGMMV was subsequently confirmed in Queensland in April 2015 and in Western Australia in July 2016.
CGMMV was first found in the United Kingdom in 1935, but it has since been identified in other European countries, India, Greece (2002), Ukraine (2007), Japan (2009), China (2009), Korea (2008), Myanmar (2010), Israel (2013) and California, USA (2013).
CGMMV belongs to the virus Genus, Tobamovirus, members of which are known for their long-term survivability. These viruses are transmitted mechanically by wounds made with cutting tools, farming equipment, or chewing insects such as beetles. They can also be passed to other plants by root grafting or any handling of the crop. Sucking insects (e.g. aphids, mites, whiteflies) do not transmit these viruses. Once the virus infects a plant, there is no known cure.
A study in India has isolated CGMMV from river and irrigation water; while in Greece the virus retained its infectivity in naturally contaminated soil after storage at 4°C for at least 10 months.
|Crops affected|| |
CGMMV infects members of the Cucurbitaceae, including:
Apart from cucurbit crop plants, CGMMV has also been found to infect the weeds Amaranthus blitoides, Amaranthus retroflexus, Heliotropium europaeum, Portulaca oleracea and Solanum nigrum and some wild cucurbit plants, such as pie melon.
The symptoms found on an infected plant will vary with the genus, species and cultivar of the plant and the strain of the virus. Symptoms described for this virus range from light yellow green spots and vein clearing on young leaves to chlorotic mottling, leaf deformation, plant stunting, and necrosis at later stages of growth. Mature leaves can become bleached and fruit drop is common.
In watermelons, symptoms include misshapen fruit with internal discolouration, rotting and necrosis.
CGMMV has been shown to be transmitted by seed.
The virus can also be transmitted mechanically by wounds made with cutting tools, farming equipment, or on the mouth-parts of chewing insects such as beetles.
Sucking insects (e.g. aphids, mites, whiteflies) do not transmit these viruses.
|Risk period|| |
Key planting periods for cucurbits in Queensland are August to December in the south, and March to June in the north.
Monitoring and action
Inspect your plants regularly for the presence of exotic pests and diseases.
Report any symptoms of Cucumber green mottle mosaic disease to Biosecurity Queensland immediately.
Biosecurity Queensland recommends that cucurbit growers ensure any seed line they purchase or use has been tested by ELISA using a sample size of 9,400 seeds in accordance with the Australian Department of Agriculture's Public Quarantine Alert (PQA1025) issued on 21 January 2015.
Producers are encouraged to adopt good on farm hygiene practices to protect their crops from viruses such as CGMMV.
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