Sydney NSW, Australia
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2018-08-21T04:00:00.0000000Z
7
Spots and wilts, cucumber - Cambodia
I received the message below and attached pictures of cucumber leaves and stems infected with diseases from Dr. Kim Hian Seng, Cambodia. We would appreciate your diagnosis and control recommendations.
MuniDear all
We have problem with Anthracnose in our cucumber trials. Last week we tried with Carbendazim, it did not work. I will try Azoxystrobin this week. Please advise an effective fungicide for anthracnose. Also, we have another disease that we suspected that it is probably Gummy Stem Blight or perhaps Bacterial Wilt? I am sending a few photos of each disease for your help in identifying them.Best regards,
Kim Hian
Cambodia
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0
2018-08-22T14:00:00.0000000Z
Dear Bob,
How are you? Long time no see you. Your recommendation about fungicides is great. I will save it for long term usage hihihi
I also agree with you, the symptom is "burning" not caused by fungus or bacteria.
Kind regards,
Phuong Dinh
0
2018-08-23T21:43:25.6024181Z
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.
The symptoms on the plants with wilted leaves are physiological. They are not affected by a disease caused by a pathogen. This problem seems to occur quite regularly in Cambodia with a lot of young crops which are fertilised by fertigation. The symptoms suggest the fertigation solution is too strong or at least too strong in one component which is causing ‘burning’ of the leaves. I suggest checking that the correct amounts of nutrients being added to the tank and making sure that they are all completely dissolved.Hope this is helpful.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
The symptoms on the plants with wilted leaves are physiological. They are not affected by a disease caused by a pathogen. This problem seems to occur quite regularly in Cambodia with a lot of young crops which are fertilised by fertigation. The symptoms suggest the fertigation solution is too strong or at least too strong in one component which is causing ‘burning’ of the leaves. I suggest checking that the correct amounts of nutrients being added to the tank and making sure that they are all completely dissolved.Hope this is helpful.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