Rust

 

 

Symptoms
Orange-brown pustules develop on the undersides of leaves. These can often go unnoticed and the disease has taken quite a hold by the time the pustules appear on the upper leaf surface and are noticed.

 

Cause
A fungus which produces spores that need a moist environment to germinate, so most bad infections are in damper places.

 

Harm
Badly affected plants can be so weakened they are unable to withstand winter frosts.

 

Treatment
Organic - remove and burn all infected leaves. Grow resistant varieties.
Chemical - spray with a systemic fungicide at the first signs of an attack.

 

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Source: Crocus - The leading online garden centre

 

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