SeedQuest - Central information website for the global seed industry

News Page

The news
and
beyond the news

Index of news sources

Topics

Species

Archives

News archive 1997-2008

Suspected cucumber green mottle mosaic virus in Queensland, Australia

A ProMED-mail post <http://www.promedmail.org>
ProMED-mail is a program of the International Society for Infectious Diseases <http://www.isid.org>

Date: Wed 22 Feb 2017

Source: Australian Broadcasting Corporation (ABC) Rural [edited] <http://www.abc.net.au/news/2017-02-22/suspected-case-of-cgmmv-in-queensland/8293922>

Suspected case of cucurbit disease

Queensland's cucurbit industry is on standby following a suspected case of cucumber green mottle mosaic virus at a greenhouse cucumber farm in the Bundaberg region. A seed company submitted samples [and] Biosecurity Queensland [BQ] now needs to undertake its own testing in order to confirm.

The Australian Melon Association [AMA] wants to know as soon as possible. [AMA's] Dianne Fullelove said the region was a significant growing area for cucurbit crops and the possibility of a CGMMV outbreak was concerning. "We are certainly encouraging growers to maintain the highest on-farm biosecurity."

Not just cucumber or melon growers need to be extra vigilant. "There is a big zucchini industry and we certainly do not want those farms infected either," she said. "BQ have still not put [a] restriction on the farm [because] they had not received the second lot of testing.

That is a concern, trucks are moving around [and] could quite easily transmit [it]."

If CGMMV is confirmed, surveillance will determine the extent of the virus. The disease was previously detected in melons in Charters Towers in 2015 [ProMED-mail post http://promedmail.org/post/20150423.3316252] and BQ is currently completing surveillance to prove [it] has been eradicated [there]. The suspected detection in the Bundaberg region is not thought to be related to the Charters Towers detection.

[Byline: Lara Webster]

Communicated by: ProMED-mail <promed@promedmail.org>

[_Cucumber green mottle mosaic virus_ (CGMMV; genus _Tobamovirus_) is a major pathogen of cucurbit crops with reported yield losses of around 15 per cent. The virus has a narrow host range. Many strains, including the type strain occurring in Europe, are limited to Cucurbitaceae, but some isolates have been reported which can also affect a number of species in other families, including Amaranthaceae and Solanaceae. Symptoms vary in different host species and may be masked in field crops. They may include severe leaf mosaic, deformation of vines and internal fruit symptoms such as discolouration and rotting of flesh.

CGMMV is both seed and pollen transmitted. It is extremely stable and can also be spread by mechanical means (human activities, insect damage, plant-to-plant contact), with contaminated agricultural tools, infected plant material, contaminated soil and in water. Spread by specific insect vectors appears doubtful. Disease management may include removal of virus reservoirs, phytosanitary practices and use of certified clean seed or other planting material. Transgenic rootstock lines of some cucurbit crops (such as watermelon) with resistance to CGMMV have been or are being developed.

In Australia, CGMMV has been detected in Northern Territory, Western Australia and Queensland in cucurbit crops (including watermelon, pumpkin), cucurbit seedlings (for example, cucumber) and a number of weed hosts (see previous ProMED-mail posts listed below). Initially, it was suggested that the virus may have entered the country with infected watermelon seed from overseas. However, its presence in multiple hosts would now suggest that the virus may have been present in the country before its 1st official confirmation (ProMED-mail post http://promedmail.org/post/20141009.2844854). Wild cucurbits, which are common in central Australia, may have provided a virus reservoir.

Alternatively, different strains may be present in crops and weeds, in which case the strain(s) affecting the crops may have been introduced on seeds. To clarify these questions, strains from the different hosts need to be characterised. However, evidence suggests that local spread occurs (see ProMED-mail post http://promedmail.org/post/20160123.3958997).

In the light of the new outbreak above apparently being linked to cucumber seed in yet another area, and considering past outbreaks have also been linked to imported seeds, the competence of the Australian seed certification process is now being questioned widely (see links below).

Maps

Australia (with states):

<http://www.webookaustralia.com/images/australiamap.jpg>

Queensland:

<http://www.sydney-australia.biz/maps/queensland/graphics/queensland-maps-australia.png>

Pictures

CGMMV affected cucurbit fruits:

<http://www.english.vkm.no/eway/imgstore/6efd6060bc.jpg> (cucumber), <https://www.agric.wa.gov.au/sites/gateway/files/cucumber%20green%20mottle%20mosaic%20virus1.jpg>

(watermelon) and

<http://www.abc.net.au/news/image/5751900-3x2-340x227.jpg>

(watermelon)

CGMMV symptoms on cucurbit leaves and vines: