A ProMED-mail post
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International Society for Infectious Diseases
http://www.isid.org
Date: Sat 29 Oct 2022 12:57 AM AEST
Source: Australian Broadcasting Corporation (ABC) Rural [summ. Mod.DHA, edited]
https://www.abc.net.au/news/rural/2022-10-28/guava-root-knot-nematode-detected-on-nt-vegetable-farms/101591160
The Northern Territory's chief plant health officer has confirmed that _Meloidogyne enterolobii_ (guava root-knot nematode) was identified on 4 properties. The nematode has never been detected in Australia before. So far, it is unknown when or how the pest arrived on the continent and how wide it has spread.
The nematode was found on sweet potato, cucumber, capsicum, butternut pumpkin, snake bean, zucchini, and chilli plants at a commercial farm, 2 residential gardens, and a community garden. No link could be found between the affected properties. A sample from 2021 thought to be a different species was re-tested and now also identified as _M. enterolobii_, indicating that the nematode has been in the Northern Territory at least since then. It appears to be widespread already.
There are no visible symptoms until plants start to fail. Growers are asked to submit any samples they might be concerned about.
[Byline: Annie Brown]
--
Communicated by:
ProMED
[Root knot nematodes (_Meloidogyne_ species) attack a wide range of plants and cause significant economic losses in many vegetable and fruit crops. The genus contains around 70 species and is found worldwide in tropical and subtropical regions in many types of soil. Symptoms may include stunting, wilting, and leaf chlorosis; large galls are formed throughout the root system affecting plant vigour and even killing the host. Affected plants may show increased sensitivity to other bacterial or fungal pathogens.
_M. enterolobii_ (synonym _M. mayaguensis_) is polyphagous and, although its precise host range is still unknown, has been found on many economically important crops including guava, potato, coffee, soybean, sweet potato, melons, and a range of vegetables. While it originates in subtropical areas, it also poses a serious threat to glasshouse crops in cooler regions. It is considered an emerging and particularly aggressive pathogen with increased virulence against crop varieties resistant to other root knot nematodes. For example, it is able to reproduce on capsicum, watermelon, tobacco, and tomato varieties (including rootstocks) resistant to other _Meloidogyne_ species.
Root knot and many other nematodes can persist in the soil for many years and are spread by plant material, soil, and mechanical means (for example contaminated equipment). Once they have been established in an area, it is difficult to control or eradicate them. Disease management is generally aimed at keeping nematode levels below economic thresholds. An integrated approach is required, including phytosanitation (exclusion), cultural measures (such as long crop rotation with non-host species), nematicides, and use of resistant crop varieties, if available.
Maps
Australia (with states):
https://www.nationsonline.org/maps/australia-political-map.jpg and
https://promedmail.org/promed-post?place=8706512,292
Pictures
Root knot (_Meloidogyne_ spp.) damage on
- sweet potato:
https://guilford.ces.ncsu.edu/wp-content/uploads/2017/05/sweet-potatoes.jpg and
https://plantpathology.ces.ncsu.edu/wp-content/uploads/2017/05/Menterolobii_sweetpotato.jpg
- potato tubers:
https://www.insectimages.org/browse/detail.cfm?imgnum=5356846 and
http://www.infonet-biovision.org/res/res/files/2171.280x185.clip.jpeg
Root knot nematode and gall:
http://ipm.ucanr.edu/PMG/IMAGES/M/N-RK-MSPP-AD.001.jpg
_Meloidogyne_ photo gallery:
https://www.insectimages.org/browse/subthumb.cfm?sub=7001
Links
Additional news story:
https://www.abc.net.au/news/2022-10-31/sweet-potato-pest-guava-root-knot-nematode-in-australia/101597732 (thanks to G Jackson, Pestnet)
Information on _M. enterolobii_:
https://gd.eppo.int/taxon/MELGMY,
https://entnemdept.ufl.edu/Creatures/NEMATODE/Meloidogyne_enterolobii_Guava_or_pacara_earpod_root_knot_nematode.htm,
http://blogs.cdfa.ca.gov/Section3162/?tag=meloidogyne-enterolobii, and
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2618283/
Information on root-knot (and other) nematodes:
http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7489.html#LIFE
Genus _Meloidogyne_ taxonomy and species list:
http://www.uniprot.org/taxonomy/189290
All other nematode taxonomy via:
https://www.uniprot.org/taxonomy/6231
- Mod.DHA
ProMED map:
Northern Territory, Australia: https://promedmail.org/promed-post?place=8706512,292]
See Also
2021
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Nematodes, pineapple - Kenya 20210514.8361061
2018
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Root knot disease, citrus & guava - India: (TN) 20180412.5743115
Meloidogyne enterolobii decline, guava - India: 1st rep (TN) 20180305.5665346
2017
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Meloidogyne enterolobii root knot, yam - Nigeria: 1st rep 20170706.5154581
2013
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Meloidogyne enterolobii root knot, potato - South Africa: (NL) 20130918.1951868
2012
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Root knot, rice - India: north, emerging disease 20120802.1225341
2009
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Meloidogyne enterolobii nematode, vegetables - Europe 20091204.4140
2008
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Meloidogyne enterolobii nematode, vegetables - Switzerland: 1st rep 20080912.2846
2007
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Quick & slow wilts, black pepper - India (Kerala) 20070807.2565
2002
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Meloidogyne mayaguensis, new pest - USA (Florida) 20020625.4597
and additional items on root knot nematodes in the archives
Topics
Species
