Don’s Expert Answers: Leaf damage

Question From: 
Geoff Prince in  rural property 35 kilometres west of Albany,  Albany WA

 

Nature of problem: 
Leaf damage

 

Type of Plant (if known): 
rhubarb, apples and some others

 

Symptoms of Plant Illness (please try NOT to diagnose your problems yourself): 
small holes in leaves with brown margins which increase in size until in some cases the whole leaf is brown

 

Soil Type (e.g. sandy, clay or loam) OR Potting Mix Type: 
sandy

 

How often do you water the plant:
irregularly

 

How many hours of sunlight does the plant get each day:
12

 

What type of plant is it:
see photo

 

How long since you planted it:
12 months (rhubarb) 15 years (apple)

 

Have you fertilised? If so, with what and when:
general NPK fertilizer

 

Is the plant indoors or outdoors: 
outdoors

 

Is the plant in a pot or in the ground: 
ground

 

What other treatments have you given the plant: 
none

Upload photo if available: 
pics3.jpg

Other Comments: 
Damage occurs in spring.

 

Answer:  Hi Geoff, this is Shothole (AKA Freckle) disease. It occurs in Spring in areas – like yours – with high Winter rainfall. Spray only in late Autumn with Bordeaux Powder or any copper fungicide or lime sulfur. Clean up all dead diseased leaves and branches. It needs to be treated every Autumn from now on since it lives inside the plants.  Don