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YELLOW SIGATOKA, LEAF SPECKLE, BANANA - AUSTRALIA: (QUEENSLAND)
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Date: Thu 25 Jun 2009
Source: North Queensland Register [edited]
<http://nqr.farmonline.com.au/news/state/agribusiness-and-general/general/bq-urges-caution-on-yellow-sigatoka/1548451.aspx>
Biosecurity Queensland urges caution on yellow sigatoka
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Biosecurity Queensland (BQ) has issued a request for growers and
backyard gardeners to check plants following an increased level of
yellow sigatoka especially in the Innisfail area.
BQ senior inspector Aaron Russell said recent wet conditions were
ideal for the spread of yellow sigatoka and other plant diseases such
as speckle disease. "Sigatoka disease can reduce crop yields and cause
premature ripening of fruit on heavily infested banana plants," he
said. "Leaf spot diseases rely on moisture from rain, heavy dew and
wind to spread to other areas. Fungal spores can travel up to 30 km
[19 mi] by air, so it is vital that all banana growers practice good
plant hygiene. Anybody who owns a banana plant needs to take action
now before yellow sigatoka or speckle disease get out of control."
Mr Russell said it was illegal within the Northern Pest Quarantine
Area, which includes Innisfail, Babinda, and Cairns, to have more than
5 percent of a banana leaf covered in leaf spot disease. "BQ will
conduct random inspections to ensure commercial and backyard banana
growers are observing the leaf disease coverage limits," he said.
"The disease is easy to manage -- just remove all leaves carrying leaf
spot from the plants as soon any spots appear. This will improve the
health of your own plants and reduce the number of airborne spores
that can infect other people's banana plants."
--
Communicated by:
ProMED-mail
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[Yellow sigatoka (YS; sigatoka leaf spot) is caused by the fungus
_Mycosphaerella musicola_. The related _M. fijiensis_ (black sigatoka,
BS; black leaf streak) as well as a number of fungal pathogens in
other genera cause similar leaf spot symptoms in different regions of
the world. In areas where more than one leaf spot pathogen is present,
it is often difficult to distinguish between them under field
conditions, and laboratory analysis may be needed for a clear diagnosis.
Symptoms and epidemiology are similar for YS and BS. YS symptoms
appear mainly on older leaves and, therefore, less damage is caused to
photosynthetic tissue than by BS. There are more cultivars of banana
and plantain with degrees of resistance to YS than to BS. YS is more
adapted to cooler temperatures and is often dominant at higher
altitudes. The pathogens are spread by water, wind, and with plant
material, including suckers, and can cause yield losses of up to 50
percent. Fruit produced on diseased plants can ripen prematurely
during commercial shipment causing further losses. Disease management
includes frequent applications of fungicides, phytosanitary measures,
and cultural practices.
Leaf speckle of banana can be caused by one or several fungal species
belonging to different genera (including _Mycosphaerella_,
_Ramichloridium_, _Metulocladosporiella_, _Acrodontium_) in different
areas of the world. Symptoms include brown lesions on the underside of
the leaf, leaf chlorosis, and progressive necrosis. Two leaf speckle
fungi reported from Australia are _Mycosphaerella musae_ and
_Ramichloridium biverticillatum_ (previously _Periconiella musae_).
These are also important fungal pathogens of banana worldwide and
often cause serious disease in the subtropics.
For the YS and leaf speckle management guidelines by Biosecurity
Queensland please see link below. Their application will be helpful in
minimising the current outbreaks.
Maps
Australia:
<http://www.ga.gov.au/image_cache/GA4073.jpg> and
<http://healthmap.org/r/008N>
Queensland:
<http://www.ozhorizons.com.au/qld/map.gif>
Worldwide distribution of BS and YS:
<http://www.apsnet.org/online/feature/banana/Images/Figure8sm.jpg>
Pictures
YS leaf spot:
<http://www.agric.wa.gov.au/ikmp/images/f04992b.gif> and
<http://www2.dpi.qld.gov.au/images/12005.JPG>
Links
Information on black and yellow sigatoka:
<http://www.oisat.org/pests/diseases/fungal/sigatoka_leaf_spot.html> and
<http://www.bioversityinternational.org/Publications/Pdf/699.pdf>
Information on YS epidemiology and control:
<http://www2.dpi.qld.gov.au/horticulture/5247.html>
Leaf speckle fungi currently not reported in Australia:
<http://www.planthealthaustralia.com.au/project_documents/TST/viewTST.asp?page=1&ID=42&filter=1&records=26&sort=1&order=2>
Leaf speckle diseases in Africa (with pictures):
<http://www.uce.co.ug/Leafspotsfactsheet.pdf> and
<http://www.cpp.uk.com/UPLOADS/publications/downloads/Perspectives%20-%20Africa%20p%2031-65.pdf>
Queensland banana leaf disease information and guidelines:
<http://www2.dpi.qld.gov.au/health/16965.html>
_M. musicola_ taxonomy:
<http://www.indexfungorum.org/Names/NamesRecord.asp?RecordID=288651>
Taxonomy of all other fungal species via:
<http://www.indexfungorum.org/Names/Names.asp>. - Mod.DHA]
[see also:
Leaf spot, banana - Caribbean region: control efforts 20090614.2204
2008
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Leaf spot, banana - St. Vincent & Grenadines 20080215.0605
2007
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Black sigatoka, banana - Philippines (Mindanao) 20071012.3351
2006
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Cavendish banana, disease susceptibility 20060521.1441
Black sigatoka, banana - Puerto Rico: 1st Report 20060413.1101
2004
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Black sigatoka, banana - Trinidad & Tobago 20040811.2223
Black sigatoka, banana - Bahamas 20040611.1568
2001
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Black sigatoka, banana - Australia (Queensland) (03) 20010422.0788
Black sigatoka, banana - Australia (Queensland) (02) 20010417.0759
Black sigatoka, banana - Australia (Queensland) 20010412.0722
Black sigatoka - Australia & Papua New Guinea 20010101.0006
2000
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Black sigatoka, bananas - Australia (Queensland) 20000731.1269
and older items in the archives]
........................................dha/mj/jw
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