What is Gummosis?

What is Gummosis? 

Gummosis is a fungal disease where sap leaks from a wound in the tree.

What causes Gummosis?

It affects stone fruit, namely peach, plum, cherry or apricots. It often occurs when the tree has a perennial or bacterial canker or is attacked by the peach tree borer. It can also be caused by any wound to a stone fruit tree, including winter damage, disease damage or damage from a gardening tool.

How to identify Gummosis

The earliest signs of fungal gummosis are the small spots on new bark that ooze resin. Over time the fungus on these spots kills tree tissue, resulting in a sunken area. On a heavily infected tree, the diseased bark begins to peel.

How to prevent Gummosis

Any action you can take to prevent bark wounds will also assist with gummosis prevention. Plant your fruit trees in the best possible wind-protected sites with well drained soils.

Keeping your tree healthy will also limit borer insect attacks and choose varieties resistant to cankers.

How to treat Gummosis

First thing to do with a tree showing gummosis is to correct any drainage problems, then amend the soil or transplant to a better site.

Ensure good garden hygiene, cleaning up all fallen leaves and plant materials on the ground (bag & bin) that may harbour the fungus.

Another step to treat, is to remove the diseased bark, removing the darkened area of bark from the tree, plus a strip of the healthy bark until the wound is surrounded by a margin of healthy bark.

Once this is done, let the area dry.

Keep monitoring the area and repeat the bark trimming if necessary.

Care after Gummosis

Promote good vigour in your tree by fertilising, watering well and ensuring your tree is never standing in water or is overly damp.

When healthy trees are infected, they can usually recover, the healthier the tree is, the more able it is to rejuvenate after infection.