Gummosis On Peach Tree - Causes And Treatment

By Harry RamosLast update: 2024-04-21

There are a lot of reasons for peach branches to die all of a sudden: broken branches, some type of infestation, diseases, etc. And gummosis is one of them.

In today’s post, I’ll dive deeply into the topic “gummosis on peach tree – causes and treatment”. Let’s get started.

What Is Gummosis On Peach Trees?

Gummosis On Peach Tree - Causes And Treatment

As mentioned, gummosis is very common in stone fruits such as peach, plum, cherry, and apricot.

It’s the sap oozing from cankers or wounds on trees.

What Causes Gummosis On Peach Trees?

The biotic cause of peach fungus gummosis (PFG) is Botryosphaeria dothidea, which infests the tree through its natural lenticels.

Gummosis On Peach Tree - Causes And Treatment

Injuries – such as pruning or peach tree borer - are another common cause of PFG. Lesser peach tree borers and peach tree borers are some common harmful insects on peach trees.

They lay eggs on tree bark near the soil line (usually from August to September and from March to May).

Gummosis On Peach Tree - Causes And Treatment

Then, the larvae bore into the tree's bark to eat vascular tissue.

Compared together, lesser peach tree borers cause fewer damages than peach tree borers.

Commonly, this doesn't lead to gummosis on healthy peach trees.

But if they're weak for some reasons - such as environmental stress, diseases, or infestation - or the plants are still young, the fungus takes the opportunity to spread.

Now, how to distinguish between gummosis caused by secondary invaders and fungus gummosis?

It's easy. Look at the oozed sap; if it contains pieces of bark or sawdust, that means gummosis is caused by secondary invaders. If it doesn't, that is fungus gummosis.

Symptoms and Diagnosis

Gummosis is commonly found around the lenticels of peach trees. The early signs are tiny spots on new bark that oozes sap.

Gummosis On Peach Tree - Causes And Treatment

Over time, sunken lesions appear on the bark, while leaves and new shoots might wilt or turn yellow because fungus on those spots kills tree tissue.

Long-term infested spots are super-gummy and possibly enlarged. More sap is oozed out.

Gummosis On Peach Tree - Causes And Treatment

Fungus chains (curly orange threads) grow out of the bark and the diseased bark starts peeling, making the peach tree develop a shaggy, rough texture.

Worse, leaves turn brown and the tree defoliates. Finally, the whole branches or the whole tree dies.

The symptoms of PFM commonly appear when peach trees come out of dormant period, usually in wet spring months when the temperatures range from 70–85 degrees F.

How To Treat Gummosis On Peach Tree

Prevent Physical Injuries

Damages on peach branches create ideal conditions to result in fungus gummosis. To reduce these risks, you should:

  • Avoid pruning when the disease is active the most (usually in the fall and winter)
  • Prune the trees properly
Gummosis On Peach Tree - Causes And Treatment
  • Carry out the right solutions to repel deer
  • Use garden equipment – such as string trimmers and lawn mowers - carefully

Harmful Insect Management

Crush the larvae by using a thin wire to probe tiny holes in the tree trunk near the soil line.

Before new shoots establish, apply dormant oil in late February when the humidity is low and the temperatures are 45-85 degrees F.

In April and May when larvae are hatching, apply Permethrin onto the infested tree trunks. If the infestation is serious, apply 3 times at 2-week intervals.

Gummosis On Peach Tree - Causes And Treatment

Do the same during August-September as a protection method.

If you still find borer holes, apply spinosad directly on the holes and those infested tree trunks weekly from mid-August to late September.

Correct Any Possible Environment Stress

Do you know that winter injuries, use of herbicides and weed killers nearby, and poorly drained soils cause environmental stresses on peach trees?

To avoid that, you should:

  • Not plant peach trees in poor, compacted soils or renovate the soil before seeding/planting
  • Irrigate under the canopy
  • Improve the soil's water drainage
  • Use herbicides following the recommended dose
Gummosis On Peach Tree - Causes And Treatment
  • Avoid pruning in the winter
  • Don’t plant peach trees in open areas with strong winds
  • With peach trees from 1-3 years old, paint their trunk and lower branches near the soil line with white latex paint
Gummosis On Peach Tree - Causes And Treatment

Manage Irrigation System And Fertilization

Peach fungal gummosis is very hard to control because the infestation can happen at any time of the year.

There are no approved fungicides to cure this disease effectively while using fungicides to protect trees becomes costly in the long run.

The most practical solution is to do good horticultural practices - such as managing irrigation systems and fertilization - to keep the trees healthy and decrease losses during PFG.

Gummosis On Peach Tree - Causes And Treatment


Gummosis on peach trees is a dangerous disease, which brings serious losses to gardeners and cultivators. Therefore, it’s essential to learn more about this disease: causes, symptoms, diagnosis, and treatment to prevent as well as reduce losses.

I hope you find this topic “gummosis on peach tree – causes and treatment” helpful. Thanks for reading!

I’m Harry Ramos, who's crazy about all things green. I’m here to share some experience in my gardening adventure and how to choose the best products for your garden. Let's dig in, get our hands dirty, and celebrate the simple, earthy pleasures of the garden together!

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