DISEASE
 
   NAME
     Collar Rot
     Phytophthora citrophthora

Description
Pathogenic, Fungal, (soil)

Symptoms
Black soft areas appear at the base of the trunk becoming harder then splitting. Gum may ooze from the affected areas and as the rot spreads the tree is ringbarked and dies. Affected trees show signs with a lack of vigour and turn blackish at the base.
 
 Ring barking 		

Source and Dispersal
The spores are dispersed by splashing rain and spread in infest the soil. 

Favoured Conditions
It prefers wet humid conditions in soil that is poorly aerated and drained around the base of trees. Weed growth around the trunk creates a favourable condition.

Affected Plants
Citrus species vary in resistance with cultivars such as ‘Eureka” or ‘ Lisbon’ as most susceptible. 

Non-chemical Control
Prepare the soil before planting or around existing trees by improving the drainage and aeration. Remove weed growth and mulches from around the base of the trunk. Current infections may be treated by exposing the surrounding soil to air, lowering the humidity and clean back damaged areas on the trunk to fresh tissue. Avoid moisture being applied to the area.
Select plant that have a resiant rootstock to the fungus.

Chemical Control
There is no satisfactory chemical control.
Note
Always read the label for registration details and direction of use prior to application of any chemicals.