Causal Agent: 

Fungus (Phoma cucurbitacearum)

Characteristic Symptoms:
 

Leaves of melon first exhibit water-soaked lesion on the leaf margin which later become wedge-shaped.

   
Infected melon stems first show water-soaked lesions. Later, lesions turn tan with numerous black pycnidia. Cracking of infected stem sometimes occur.
   
Conditions for Disease Development
 
Optimum temperatures for infection are 25-32ºC but moisture is more important for disease development than temperature.
   
The gummy stem blight fungus is both seed- and soil-borne.
   
Management and Control:
 
Use disease-free seed.
   
Maintain good field sanitation (e.g. remove & burn affected plant/plant parts).
   
Crop rotate with non-host crops for at least 18 months.
   

Apply fungicides such as  pyraclostrobin+dimetomorph (e.g. Cabrio Team®), thiophanate methyl (e.g. Tango®, Topsin®) or metalaxyl+mancozeb (e.g. Ridomil®),carbendazim ( (Bavistin 50 DFⓇ, Goldazim 500 SSⓇ, Minx 500 SCⓇ, SuperdazimⓇ, Avert 50 WPⓇ, BiostinⓇ), difenoconazole (e.g. ScoreⓇ, MontanaⓇ, PursueⓇ, BashⓇ), Difenoconazole+proficonazole (e.g. ArmureⓇ), Pyraclostrobin (e.g. Cabrio 25 ECⓇ).
 

 

References:

http://vegetablemdonline.ppath.cornell.edu/factsheets/Cucurbit_GSBlight.htm

https://edis.ifas.ufl.edu/pp280

 

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