DISEASE

NAME
Lichens
Various Lichen Species


Description
A fungus and an alga growing in a symbiotic relationship. The food producing alga is given support and shelter by the fungus.

Symptoms
Lichens are variable, occurring in many shapes, sizes and colours from flat to circular and may be leaf like crinkly or hairy. The colour also varies from greenish grey to yellow or orange. They occur on many surfaces including tree trunks, rocks, fences and roof tiles. They cause little harm to living plants and certain types are attractive while others are unsightly.

Fagus sylvatica               

Source and Dispersal
Contaminated areas, and is dispersed by wind or splashing water.

Favoured Conditions
Conditions are variable as some types prefer cool moist situations while others tolerate open exposed positions.

          
     
Affected Plants
There are many plants that form lichens on the bark, particular old woody trees that are in shaded moist positions. Shrubs and Palms also form coverage of lichens on there stems under moist conditions.

Archontophoenix cunninghamiana     

Non-chemical Control
Under normal circumstances, unnecessary but lichens can be removed by scraping or scrubbing.

Chemical Control
Not normally required but lichens can be killed by spraying the fungicide copper oxychloride but take care as the chemical may damage certain building materials.
Note
Always read the label for registration details and direction of use prior to application of any chemicals.