Sydney NSW, Australia
Request for information
2018-10-29T17:00:00.0000000Z
2
Cucumber disease, Corynespora cassiicola, Pohnpei - Federated States of Micronesia
Dear Pestnetters
Cucumber is a very important crop in Pohnpei, Micronesia. Unfortunately, a fungus disease comes in, soon after the crop starts producing and it destroys it. According to my literature search it is Corynespora cassiicola ? Farmers in Micronesia do not spray fungicides. According to the literature “ the fungus is probably a secondary invader of rotting fruits of papaya and tomato.”
Cucumber is a very important crop in Pohnpei, Micronesia. Unfortunately, a fungus disease comes in, soon after the crop starts producing and it destroys it. According to my literature search it is Corynespora cassiicola ? Farmers in Micronesia do not spray fungicides. According to the literature “ the fungus is probably a secondary invader of rotting fruits of papaya and tomato.”
Does anyone have recommendations on what we can do? Do we need to keep an eye on the papaya? Is there anything else besides using fungicides to control the disease?
I look forward to get some expert advise.
Kind regards,
Konrad
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Responses
0
2018-11-01T14:00:00.0000000Z
Dear Konrad
This is a severe disease of cucumber in many Pacific islands. Corynespora is also a severe disease of tomato, known to some as target spot. And as you suggest it is common on papaya, although on that host the damage is minimal..
You have asked for suggestions on controlling Corynespora without fungicides. In your very high rainfall that is going to be a challenge. Some cultural control practices are suggested in a Pestnet fact sheet that might help, and they can be found by going to the website and clicking on Pest Fact Sheets.
However, a more fruitful approach might be to write to seed companies and ask them if they can suggest varieties that might have some tolerance. I would also write to AVRDC for information: https://avrdc.org/seed/improved-lines/cucumber/. Mildews are mentioned but not your pathogen.
If indeed you have to recommend fungicides, you might wish to considered Bob Fullerton's comments on a spot disease of cucumber from Cambodia. I am copying Bob's recommendations below. You can see the entire email - which was sent to Pestnet on 22 August 2018 - if you go to the archives.
Best wishes
grahame
From Bob Fullerton 22 august 2018
"Carbendazim is prone to resistance and it is possible that the local strains of Colletotrichum may be resistant if carbendazim has been used regularly for a long time. Azoxystrobin is a very effective fungicide with some curative activity but is also very prone to resistance. I always recommend using it in combination with a protectant such as mancozeb or chlorothalonil, or a fungicide with curative activity such as difenoconazole. The product Amistar Top is a combination of azoxyxtrobin + difenoconazole both of which have curative properties. Because it is purchased as a mixture it is very convenient to use. It is available in Cambodia".
Kind regards
Bob FullertonPrincipal Scientist
T: +64 9 925 7131
M: +64 212268131
F: +64 9 925 7001
E: bob.fullerton@plantandfood.co.nz
www.plantandfood.co.nz
The New Zealand Institute for Plant & Food Research Limited
0
2018-11-06T21:15:49.0000000Z
| |
Yes, as a general rule most fungicides will control most (above ground) fungal diseases though some of course are better at it than others. For small plots or gardens you cant respond individually to each disease so rotating a few fungicides, some of the older actives with protectant activity and some of the more modern ones with locally systemic activity should keep most things at bay. But you usually need to scout and start early – well before it reaches epidemic stage.
Bob Fullerton
Principal Scientist
T: +64 9 925 7131
M: +64 212268131
F: +64 9 925 7001
E: bob.fullerton@plantandfood.co.nz
www.plantandfood.co.nz
The New Zealand Institute for Plant & Food Research Limited
Postal Address: Plant & Food Research
Private Bag 92169, Auckland Mail Centre, Auckland 1142, New Zealand
Physical Address: Plant & Food Research
120 Mt Albert Road, Sandringham, Auckland 1025, New Zealand
Posted on user's behalf
Principal Scientist
T: +64 9 925 7131
M: +64 212268131
F: +64 9 925 7001
E: bob.fullerton@plantandfood.co.nz
www.plantandfood.co.nz
The New Zealand Institute for Plant & Food Research Limited
Postal Address: Plant & Food Research
Private Bag 92169, Auckland Mail Centre, Auckland 1142, New Zealand
Physical Address: Plant & Food Research
120 Mt Albert Road, Sandringham, Auckland 1025, New Zealand
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0
2018-11-08T14:00:00.0000000Z
'Konrad Englberger' konrad.englberger@gmail.com [pestnet] <pestnet@yahoogroups.com> |
| Dear Grahame and Bob, |
Thank you for the information. Besides the leaf spots (Corynespora), Gummy stem blight (Didymella bryoniae) is another major problem. I have been using mancozeb in my garden on cucumber and tomato but did not get a good control. I should test one of the fungicides Bob has suggested (azoxyxtrobin + difenoconazole) I have to see where and how to get it.I suppose these fungicides will be effective to both, Leaf spots and Gummy stem blight?Kind regards,
Konrad
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Konrad
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