BPOA technical chairman Nigel Crosby said: "It is vital that any diseased plants and debris that might have ended up in displays or gardens is removed as soon as possible.
"Look out for early symptoms such as leaves that turn pale on their upper side followed by a white discoloration on the underside. These will eventually turn yellow and fall off."
The BPOA said to remove dying plants from beds and dispose of them to landfill. Do not dig in plant material into beds or include in compost. Avoid planting impatiens into beds where plants have died unexpectedly. Use other bedding plant species in areas where the disease is suspected to have occurred previously.
This disease is specific to impatiens and does not present a risk to other bedding plant species.