Identification request
2021-08-11T21:06:12.3263350Z
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Algal leaf spot in Guava(leaves and fruits)
Hi everyone, Please kindly have a look at the photos and confirm if this is Cephaleuros virrscens Kuntze. Our Kuava trees in our compound are badly infected by this algae...suggestions and recommendations on suitable management and treatment are very much appreciated.

Responses

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2021-08-11T14:00:00.0000000Z

Hi Ange

There's a fact sheet in the app Pacific Pests Pathogens & Weeds on algal leaf spot (148). Images look a little different from yours. They are usually quite furry. The fact mentions Samoa. Younger leaves might show more definite symptoms.

Looking at what's recorded in Samoa and other Pacific island countries, other than algal leaf spots, there are a number of other causes of leaf spots worth considering. In Samoa, there is Pestalotiopsis, and elsewhere Colletotrichum, and Cercospora. So look at the spots on the fruits and leaves and see if you can see any sporulation. The spores of all these fungi are fairly distinct.

If in doubt have a look at the excellent manuals of Eric McKenzie - Pathogen Identification Manual 2&3 Export Commodities. Pest identification workshop. Landcare Research. NZ. There are nice images of Cephaleuros (sporangiophores and sporangia) on other crops as well as the equivalent structures of those three fungi I mention. I am sure Biosecurity would have copies, if they are not at SROS.

grahame

2021-08-12T01:17:48.1327996Z
Thanks Grahame... appreciate your feedback. I can isolate the fruiting bodies and look at the spores closely.
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2021-08-11T21:32:19.1505861Z
Could it be Cephaleuros parasiticus?