Causal Agent: 

Fungus (Colletotrichum sp.)

Characteristic Symptoms:
 
Affected leaves have brown necrotic spots with yellow halo and have a tendency to elongate along the veins.
   
Affected stems initially have numerous oily spots, which elongate and turn into yellowish gray sunken lesions that are sometimes covered with pinkish spore masses.
   
Fruits have oval, sunken or depressed, dark gray to brownish black lesions.
   
Conditions for Disease Development:
 
The pathogen survives between crops on infected plant residue or infected volunteer plants and can be carried on seed harvested from infected fruit.
   
Conidia/spores produced on foliage are disseminated by wind, rain splashes, tools/implements and field workers.
   
Humid, rainy weather favours infection.
   
Management and Control:
 
Use pathogen-free seed.
   
Remove and dispose infected plants/plant parts as soon as symptoms are observed to minimize spread of disease.
   
Avoid overhead irrigation or prolonged moisture to minimize disease incidence and severity.
   
Staking increases air movement and may help reduce infection in the field.
   
Deep plowing of crop residue immediately after harvest can effectively reduce inoculum carryover.
   
Crop rotation with non-cucurbit crops for at least 1 year may help reduce inoculum in the soil.
   
Spray with chemical fungicides like copper-based fungicides (e.g. Cupravit®, Super BlueⓇ, Vitigran blueⓇ, FunguranⓇ, KocideⓇ, Hydroxide superⓇ), difenoconazole (e.g. ScoreⓇ, MontanaⓇ, PursueⓇ, BashⓇ), difenoconazole+proficonazole (e.g. ArmureⓇ), Pyraclostrobin (e.g. Cabrio 25 ECⓇ),  Bacillus subtilis strain QST 713 (e.g. Serenade®, Virtuoso®) and azoxystrobin (Amistar®, MiradorⓇ, RobatoⓇ).
   
References:
Compendium of Cucurbit Diseases (1996) by the American Phytopathological Society
   

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