A ProMED-mail post
http://www.promedmail.org
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International Society for Infectious Diseases
http://www.isid.org

Date: Tue 7 Jun 2022
Source: The Informer Ug [summ. Mod.DHA, edited]
https://theinformerug.com/2022/06/07/strange-onion-disease-ravages-ntungamo-district-famers-count-losses/


New strange diseases "onion blotch" and "dumping off" have been spotted in onions and cabbage crops in Ntungamo district. The diseases have already attacked a number of gardens causing losses. Farmers have used some agrochemicals but in vain. They were advised to apply some different new chemicals and to consider planting seasons since too much rain causes diseases like the ones observed.

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Communicated by:
ProMED

[A large number of fungal, bacterial, and nematode pathogens, as well as several viruses and phytoplasmas, are known to affect onion (_Allium cepa_) and related crops. "Onion blotch" above may refer to purple blotch caused by the fungus _Alternaria porri_ which has previously caused losses in the region (e.g. ProMED post 20210607.8431139).

A range of pathogens affecting brassica crops (including cabbages, turnips, and oilseed rape) has been reported. "Dumping off" above may refer to _Rhizoctonia solani_, a ubiquitous soil borne fungus associated with damping-off and a range of rots (root, stem, fruit) in a large number of crops, including brassicas, other vegetables, cereals, and pasture grasses cabbages. For more information see previous ProMED posts in the archives.

Reliable diagnosis of the specific pathogen(s) involved is always required for designing effective management strategies for any local situation.

Maps
Uganda:
http://www.nationsonline.org/maps/uganda-political-map.jpg and
https://promedmail.org/promed-post?place=8703857,22957
Uganda districts:
http://en.wikipedia.org/wiki/Districts_of_Uganda
Africa (overview):
https://ontheworldmap.com/africa/africa-map-max.jpg

Pictures
Photo galleries of some diseases of
- onion:
http://www.ipmimages.org/browse/AreaSubs.cfm?area=86 and
- cabbages:
https://www.ipmimages.org/browse/Areathumb.cfm?area=91

Links
Information on major onion diseases:
http://www.ipm.ucdavis.edu/PMG/selectnewpest.onion-and-garlic.html,
http://www.omafra.gov.on.ca/english/crops/facts/95-063.htm,
https://tuyisengemoses.wordpress.com/2017/05/25/oniononiononiononion-disease/, and
http://vegetablemdonline.ppath.cornell.edu/factsheets/Onions_List.htm
Information on some cabbage diseases via:
https://www.agric.wa.gov.au/broccoli/diseases-vegetable-brassicas?page=0%2C1 and
http://vegetablemdonline.ppath.cornell.edu/factsheets/ColeCrops_List.htm
Lists of major diseases and pathogens of the crops via: https://www.apsnet.org/edcenter/resources/commonnames/Pages/default.aspx
- Mod.DHA]

See Also

Undiagnosed disease, onion - Taiwan 20220203.8701233
2021
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Purple blotch, onion - Nigeria: impact 20210607.8431139
Rhizoctonia diseases, potato - UK: alert 20210518.8367314
Undiagnosed root rot, onion - India: (TN) 20210202.8156911
2020
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Purple blotch & undiagnosed bulb rot, onion - India: (KA) 20200903.7741820
Anthracnose twister complex, onion - India: (KA) 20200518.7351461
2019
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Rhizoctonia, oilseed rape - UK: (England) 20191105.6762228
Undiagnosed diseases, onion - Nigeria: (KE) 20191101.6756854
2018
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Blight diseases, coffee & vegetable crops - Kenya 20180604.5837538
2016
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Stemphylium blight, onion - Kenya: (KB) 20160104.3910614
2013
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Purple blotch, onion - Kenya: (RV) susp. 20130307.1574551
2011
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Undiagnosed disease, onion - Nigeria: (KE), RFI 20110117.0196
2010
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Brassica diseases - UK: alert 20100802.2590
and additional items on diseases of the crops in the archives

Website: http://www.isid.org

Published: June 15, 2022