Scorch

This is a general term used for a leaf or stem condition which can be symptomatic of a large number of different disorders or pathogens.

Scorch gives a stem tip or leaf the appearance that it has been held close to a flame and gone brown, red-brown or black as a result. Patches initially can be coloured yellow or purplish, then gradually enlarge and become brown or black. Often affected leaves will wither but remain on the plant.

Scorch can be caused by a variety of different factors, including:

• Infection by a pathogen (particularly fungal diseases).
• Environmental conditions such as wind scorching plants in exposed sites or frost.
• Drought or under-watering (in these cases the scorch may be prevalent on lower leaves).

The natural death of leaves can appear similar to scorch, particularly on evergreens where browned leaves are often seen in the summer as the plant naturally loses some of its older leaves.