Causal Agent: 

Fungus (Colletotrichum spp.)

Characteristic Symptoms:
 
Affects both foliage and fruits but is less common in tomato fruit.
   
Affected tomato leaves have yellowish, brownish or dark gray necrotic spots with dark brown edges and concentric rings.
   
Fruits may be infected at the early stage but symptoms are expressed at maturity when conditions are favorable for infection
   
Conditions for Disease Development:
 
The fungus is soil-borne and overwinters on plant debris. 
   
The pathogen has a broad host range.
   
Spores produced on foliage can be carried through rain splashes to the developing green fruit.
   
Although symptoms do not appear until the fruit is ripening, the infection actually occurs when fruits are small and green.
   
The fungus is activated by exposure of the fruit to low temperatures, fruit maturation or plant stress.
   
The disease is favoured by warm temperature and frequent rainfall.
   
Management and Control:
 
Remove and dispose infected plants/fruits 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.
   
Remove weeds that may serve as alternate hosts of the fungus.
   
Crop rotation for 2-3 years may help reduce inoculum in the soil.
   
Use pathogen-free seed.
   
Apply copper-based fungicides (e.g. Cupravit®, Super BlueⓇ, Vitigran blueⓇ, FunguranⓇ, KocideⓇ, Hydroxide superⓇ) at early fruit set when conditions are favorable.  Application of other fungicides like 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Ⓡ).
   
Harvest fruit before it fully ripens.
   
Application of other fungicides like 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:
Tomato Anthracnose (http://www.extension.umn.edu/yardandgarden/ygbriefs/p250tomatoanthracnos... http://ohioline.osu.edu/hyg-fact/3000/3114.html; http://www.plantpath.ksu.edu/doc761.ashx)
   

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