Anthracnose: How to Identify, Treat & Prevent It in Australia

Black spots on fruit. Sunken lesions on stems. Brown patches spreading across leaves after a run of wet weather.

If that sounds familiar, anthracnose could be the culprit.

Anthracnose is the name given to a group of fungal diseases that can affect leaves, stems, flowers and fruit on a huge range of plants. Mangoes, avocados, tomatoes, beans, grapes, cucurbits, ornamentals and even turf can all be affected, although the exact symptoms and severity depend on the plant and the fungus involved.

For Aussie gardeners, anthracnose tends to become most noticeable when susceptible plants combine with the conditions these fungi love: moisture, prolonged leaf wetness, humidity and infected plant material hanging around the garden.

The good news?

Finding anthracnose doesn't automatically mean the plant is cactus.

The trick is identifying the problem early, removing sources of infection, changing the conditions that help it spread and using an appropriate treatment only when it's genuinely needed.

Here's how.

Table of Contents

• What Is Anthracnose?
• What Does Anthracnose Look Like?
• Anthracnose Symptoms by Plant
• What Causes Anthracnose?
• How Does Anthracnose Spread?
• Conditions That Make Anthracnose Worse
• How to Treat Anthracnose
• Can Anthracnose Be Cured?
• How to Prevent Anthracnose
• Anthracnose on Mango Trees
• Anthracnose on Tomatoes
• Anthracnose on Avocados
• Anthracnose on Beans
• Anthracnose on Cucumbers, Pumpkins and Melons
• Anthracnose in Lawns
• Anthracnose vs Other Plant Diseases
• A Simple Anthracnose Action Plan
• Frequently Asked Questions About Anthracnose
• Final Word: Beat Anthracnose by Changing the Conditions
• Next Reads for Managing Fungal Disease in the Garden

If you want the quick fix: start by removing infected growth cleanly, then use a plant-protection product only where its label and directions suit your plant and disease situation:

What Is Anthracnose?

Anthracnose isn't one single disease caused by one single fungus.

It's a general name used for a number of fungal diseases, many of which are associated with fungi in the Colletotrichum group.

Different species can attack different plants, which is why anthracnose on a mango doesn't necessarily behave exactly like anthracnose on a tomato, bean plant or lawn.

What they often have in common is the type of damage they produce.

Typical anthracnose symptoms include:

• Brown, black or tan leaf spots
• Dark lesions along stems or leaf veins
• Sunken spots on fruit
• Rotting fruit
• Dieback of young shoots
• Blossom or flower damage
• Premature leaf drop
• Pink, salmon or orange-coloured spore masses in some infections
• Enlarging patches of dead plant tissue

One of the biggest traps is assuming that every dark leaf spot is anthracnose.

It isn't.

Black spot, bacterial diseases, other fungal leaf spots, nutrient problems, physical damage and watering stress can sometimes produce similar-looking symptoms.

So before reaching for a spray bottle, have a proper look at the plant.

What Does Anthracnose Look Like?

Anthracnose often starts as relatively small areas of damaged tissue before the lesions enlarge.

On leaves, look for irregular brown, tan or black spots. Lesions may follow leaf veins or merge into larger dead areas as the infection progresses.

On stems and shoots, infected areas may become dark, sunken or cracked. Young shoots can die back when infection is severe.

On fruit, anthracnose commonly produces round, dark and sunken lesions. These may expand as the fruit ripens and can eventually lead to significant rot.

In damp conditions, some anthracnose infections can produce pinkish, orange or salmon-coloured spore masses within the lesions.

That combination of dark, sunken tissue + spreading damage + wet or humid conditions is worth investigating further.

Anthracnose Symptoms by Plant

Because anthracnose doesn't look identical on every host, identifying the affected plant is one of the quickest ways to narrow things down.

A quick diagnosis tip

Don't diagnose anthracnose from colour alone.

Instead, look at the pattern of damage, plant species, recent weather, presence of sunken lesions and whether symptoms are spreading after wet conditions.

If the symptoms don't fit, don't spray just because the leaves have spots.

What Causes Anthracnose?

Anthracnose develops when a susceptible plant, an appropriate pathogen and favourable environmental conditions line up.

Moisture is a major part of that equation.

Spores can be produced on infected leaves, twigs, stems, fruit and other plant material. Water then helps move those spores onto healthy tissue.

This means a garden can become far more vulnerable when plants remain wet for extended periods.

Common risk factors include:

• Frequent rain
• High humidity
• Prolonged leaf wetness
• Overhead irrigation
• Dense foliage with poor airflow
• Infected leaves or fruit left around plants
• Diseased pruning material
• Susceptible plant varieties
• Repeatedly growing susceptible crops in the same area
• Infected propagation material or seed in diseases where these are known pathways

Anthracnose isn't caused simply because you “watered too much”.

But repeatedly wet foliage and slow drying can create much better conditions for infection and spread.

How Does Anthracnose Spread?

This is where prevention starts to make a lot more sense.

Anthracnose fungi can survive on infected plant material and produce spores when conditions favour disease development.

Those spores may then reach healthy plant tissue through mechanisms such as:

• Rain splash
• Splashing irrigation water
• Infected leaves and fruit
• Diseased stems and twigs
• Contaminated crop residue
• Infected seed or planting material in some hosts

Picture a heavily infected leaf sitting below a plant.

Rain hits it.

Tiny droplets splash upwards.

Those droplets can move fungal material onto fresh leaves, stems, flowers or fruit nearby.

That's why clean-up and watering technique are actual disease-control tools, not just jobs that make the garden look tidy.

Conditions That Make Anthracnose Worse

Anthracnose is strongly associated with moisture, but there isn't one magic temperature or weather rule that applies to every host and every anthracnose fungus.

That's important.

You'll sometimes see gardening advice treat “anthracnose” as though it were one organism with one exact set of preferences. In reality, different anthracnose diseases occur on different hosts.

As a practical gardener, focus on the conditions you can control.

1. Long periods of wet foliage

Leaves that remain wet for extended periods give many fungal diseases a much better opportunity to establish.

2. Poor airflow

Dense canopies dry slowly.

A crowded plant can still be damp inside long after its outer leaves look dry.

3. Overhead watering

If disease pressure is already present, regularly wetting the foliage can make management harder.

4. Infected plant debris

Leaves, rotten fruit and diseased stems can act as reservoirs for future infection.

5. Repeated wet weather

Several rainy or humid days in a row can create an ideal window for disease to gain momentum.

That's why your best anthracnose treatment program starts with the garden environment, not the bottle.

How to Treat Anthracnose

Already found suspicious lesions?

Here's the practical order we'd tackle it in.

1. Remove Badly Infected Material

Start by removing heavily infected leaves, fruit, shoots or stems where doing so is appropriate for the plant.

You're reducing the amount of diseased material sitting there producing or carrying fungal spores.

Don't go berserk and strip every leaf off a stressed plant.

The goal is to remove obvious infection while leaving enough healthy foliage for the plant to function.

Use clean, sharp tools for pruning.

2. Pick Up Fallen Leaves and Fruit

Don't leave infected fruit turning to mush beneath the plant.

Likewise, remove diseased leaves and obvious infected crop residue.

Reducing this material can help break the reinfection cycle.

For badly diseased material, adding it straight back around the same susceptible plants generally defeats the purpose of cleaning up.

3. Change How You Water

If you've been giving the whole canopy a shower every evening, now's a good time to change tactics.

Where practical, water the soil or root zone rather than the foliage.

Morning watering is also useful because any foliage that does become wet has a better chance to dry during the day.

The aim isn't to keep a garden bone dry.

It's to avoid unnecessarily creating long periods of leaf wetness.

4. Open Up Dense Growth

Pruning can improve airflow through overcrowded plants and fruit trees.

Better airflow means faster drying.

Remove crossing, damaged or badly congested growth where appropriate for that particular plant.

Again, don't butcher the thing.

Thoughtful pruning is the goal.

5. Clean Your Tools

If you're cutting diseased material, clean pruning tools before moving onto healthy plants.

It's a simple habit and especially worthwhile whenever you're dealing with an unidentified disease.

6. Decide Whether a Fungicide Is Actually Needed

This is where people often jump too quickly.

A fungicide can't undo a dead patch of leaf or magically turn rotten fruit healthy again.

Its role depends on the product and disease: some treatments are primarily protective, some help suppress active disease, and the permitted uses vary by product and crop.

For a broader breakdown of how different fungal treatments work, have a read of our Best Organic Fungicides in Australia guide.

What about Lime Sulphur?

Kendon Lime Sulphur is a contact fungicide, miticide and insecticide in the Dr Greenthumbs range. Its current product information specifically lists fungal problems including powdery mildew, rust and black spot, alongside several pest uses.

We don't recommend assuming that a product labelled for one fungal disease automatically treats anthracnose.

If you're considering any fungicide for anthracnose, check the current product label for your specific crop, disease and application and follow those directions exactly.

That's particularly important for edible crops.

Good disease management is about using the right tool for the right problem—not spraying everything with the strongest-smelling bottle in the shed.

Can Anthracnose Be Cured?

This depends on what you mean by “cured”.

Existing dead or rotten plant tissue won't turn healthy again.

A black, sunken lesion on a piece of fruit isn't going to reverse itself after spraying.

The practical objective is to:

1. Remove badly infected material where appropriate.
2. Reduce sources of fungal spores.
3. Slow or stop new infections.
4. Protect healthy growth.
5. Make the growing environment less favourable for another outbreak.

A plant can often continue producing healthy new growth if disease pressure is brought under control and the plant itself remains vigorous.

Severely infected plants, however, can suffer major defoliation, fruit loss, shoot dieback or general decline.

Early action makes life much easier.

How to Prevent Anthracnose

Prevention is where you get the biggest bang for your buck.

Once you've had anthracnose in a garden, don't simply wait for the same spots to appear next season.

Change the conditions that allowed disease pressure to build.

Water the Roots, Not the Leaves

Use drip irrigation, a watering wand or careful hand watering where practical.

Less unnecessary foliage wetness means fewer opportunities for moisture-loving diseases.

Water Earlier in the Day

If leaves do get wet, daylight and airflow help them dry.

Repeatedly soaking foliage late in the evening can leave plants wet for hours.

Give Plants Enough Space

Tiny seedlings become big plants surprisingly quickly.

Spacing that looked generous at planting time can become a humid jungle later in the season.

Allow air to move through the canopy.

Prune Dense Plants Appropriately

Fruit trees and larger shrubs may benefit from selective pruning that lets light and airflow into the canopy.

The right method depends on the species, so prune for the plant—not simply for the fungus.

Remove Diseased Debris

Old infected fruit, leaves and stems shouldn't be allowed to accumulate indefinitely around susceptible plants.

Clean gardening matters.

Rotate Susceptible Crops Where Appropriate

In vegetable gardens, crop rotation can help with diseases that survive on infected crop material.

Rotation isn't relevant in exactly the same way to a permanent mango or avocado tree, obviously.

Match the technique to the plant.

Start With Healthy Planting Material

Where anthracnose can be carried in seed or propagation material, starting clean matters.

Healthy seedlings and disease-free planting material remove one possible pathway before your crop even gets going.

Monitor During Wet Weather

You don't need to stare at every leaf with a magnifying glass each morning.

But after prolonged rain or humid conditions, have a quick stickybeak.

Look at:

• New growth
• Lower leaves
• Crowded sections of canopy
• Flowers
• Developing fruit
• Previously affected areas

Finding the first few lesions is much easier to manage than finding half the canopy infected three weeks later.

Anthracnose on Mango Trees

Mango anthracnose deserves special attention in Australia because it can affect leaves, flowers and fruit.

One of the frustrating things about mango anthracnose is that fruit can look reasonably healthy earlier in development and show much more obvious disease as it approaches ripeness.

Typical mango anthracnose symptoms can include:

• Dark spots on leaves
• Lesions on young growth
• Flower and blossom damage
• Reduced fruit set after severe blossom infection
• Small dark spots on fruit
• Enlarging black or sunken lesions as fruit ripens
• Fruit rot in advanced infections

For backyard mango growers, prevention should focus heavily on orchard hygiene and moisture management.

Remove infected material where practical, keep fallen fruit cleaned up and maintain reasonable airflow through the canopy.

Mangoes are long-lived trees, so think of anthracnose management as a season-to-season program, not a one-off rescue spray.

We'll cover mango anthracnose treatment in more depth in its own dedicated guide.

Anthracnose on Tomatoes

Tomato anthracnose is most obvious on fruit.

It commonly appears as small, round, sunken lesions that increase in size as the fruit ripens.

This is one reason fruit hygiene matters so much.

Pick ripe tomatoes rather than leaving them hanging indefinitely, remove badly diseased fruit and keep affected fruit from rotting beneath plants.

Watering at soil level rather than repeatedly wetting tomato foliage and fruit is another sensible preventative measure.

If spots appear mainly on the leaves rather than the fruit, don't immediately assume anthracnose—tomatoes can suffer from several diseases with overlapping symptoms.

Anthracnose on Avocados

Avocado anthracnose can be especially frustrating because symptoms may become much more obvious as fruit ripens.

Look for dark lesions that enlarge and become sunken as infection develops.

Good canopy management, removal of diseased material and reduction of prolonged wetness form part of an integrated approach.

If you're treating avocado trees with any crop-protection product, check that the current label specifically permits its use on avocados for the intended disease.

Anthracnose on Beans

Anthracnose on beans can affect leaves, stems, pods and seed.

Symptoms may include reddish-brown to dark lesions along leaf veins, stems or pods.

Because some bean anthracnose infections can be associated with infected seed, disease-free seed and good crop hygiene are particularly valuable.

Remove affected crop residue and avoid saving seed from plants showing obvious disease symptoms.

Crop rotation can also form part of a sensible preventative program in veggie beds.

Anthracnose on Cucumbers, Pumpkins and Melons

Cucurbits including cucumbers, melons and pumpkins can develop anthracnose lesions on leaves, stems or fruit.

Warm-season cucurbits often grow into dense canopies, and that creates an important management challenge: airflow.

Avoid packing plants so tightly that foliage stays damp for hours after every watering or shower.

Remove severely affected material and monitor developing fruit closely.

Be particularly careful with fungicide recommendations on cucurbits because some products or formulations can cause plant injury under unsuitable conditions.

Read the label every time.

Anthracnose in Lawns

Turf anthracnose is its own specialist topic.

In lawns it can present as yellowing, browning, thinning turf and patches of decline rather than the obvious sunken fruit lesions associated with anthracnose on some crops.

Turf stress, mowing practices, nutrition, moisture and environmental conditions can all affect how disease expresses itself.

If you're diagnosing a lawn problem, don't assume every brown patch is anthracnose.

Heat stress, hydrophobic soil, other fungal diseases, insects and irrigation problems can look surprisingly similar from standing height.

A separate lawn diagnosis is the smarter approach.

Anthracnose vs Other Plant Diseases

Getting the diagnosis right matters because similar-looking problems can require completely different management.

Anthracnose vs Black Spot

Both can produce dark lesions.

Black spot is especially familiar to rose growers, whereas anthracnose is a broader disease name covering infections across many host plants.

The plant species and lesion pattern matter.

Anthracnose vs Powdery Mildew

Powdery mildew is usually much easier to recognise because of the characteristic white or grey powdery growth across foliage.

Anthracnose more commonly produces necrotic spots, sunken lesions and rotting tissue.

If your plant looks like someone dusted it with flour, our Australian powdery mildew treatment guide is the better place to start.

Anthracnose vs Bacterial Leaf Spot

Bacterial and fungal diseases can produce surprisingly similar leaf lesions.

This is another reason we don't recommend treating every spotted leaf with a random fungicide.

Look at the entire symptom pattern and host plant before deciding what you're dealing with.

Anthracnose vs Nutrient Problems

Nutrient issues usually produce broader patterns such as chlorosis, interveinal yellowing, marginal burn or abnormal growth rather than classic expanding sunken fungal lesions.

But stressed plants can also have several things going wrong at once.

Diagnosis beats guessing.

A Simple Anthracnose Action Plan

If you've just found suspicious spots and want the short version, do this:

Step 1: Identify which plant is affected.

Step 2: Look for typical anthracnose symptoms, especially dark or sunken lesions.

Step 3: Remove badly infected leaves, fruit or shoots where appropriate.

Step 4: Clean up fallen diseased material.

Step 5: Stop unnecessarily wetting the foliage.

Step 6: Improve airflow around crowded plants.

Step 7: Monitor nearby plants for new symptoms.

Step 8: If a fungicide is warranted, confirm that its current label covers your crop, disease and intended use.

Step 9: Keep monitoring new growth rather than judging success by already damaged tissue.

That's the bit worth remembering.

Old lesions tell you what already happened. New growth tells you whether your management is working.

Frequently Asked Questions About Anthracnose

Is anthracnose contagious to other plants?

Anthracnose can spread when fungal spores move from infected material onto susceptible healthy tissue. Rain splash and wet conditions are common contributors.

However, anthracnose isn't one single fungus capable of infecting every plant in the garden. Different pathogens have different host ranges.

Does anthracnose stay in the soil?

Some anthracnose fungi can persist between seasons on infected crop debris, seed, twigs or other host material.

For the home gardener, the practical response is good sanitation: remove obvious diseased material and avoid letting infected debris accumulate.

Can anthracnose kill a plant?

Severe anthracnose can seriously weaken plants through defoliation, shoot dieback, blossom damage and fruit loss.

Whether it kills a plant depends on the host, pathogen, disease severity, plant health and growing conditions.

Can a plant recover from anthracnose?

Yes, many plants can recover when infection is brought under control and healthy growing conditions return.

Already damaged tissue generally won't repair itself, so watch the new growth to judge recovery.

Should I remove leaves with anthracnose?

Removing badly infected leaves can reduce disease pressure, but don't strip a plant bare.

Take out the worst affected material and balance disease removal with the plant's need to retain healthy foliage.

Does overwatering cause anthracnose?

Overwatering doesn't magically create anthracnose—the pathogen still needs to be present.

However, excessive moisture, overhead watering and prolonged leaf wetness can produce conditions that favour infection and spread.

Does anthracnose come back every year?

It can.

If infected plant material remains in or around the garden and favourable conditions return, anthracnose may reappear.

That's why prevention and garden hygiene matter even after symptoms disappear.

When should you treat anthracnose?

Act as soon as you've reasonably identified the problem.

Early management should focus on removing infected material, improving airflow, cleaning the area and reducing unnecessary leaf wetness.

If a fungicide is required, many protective treatments work far better when used according to label directions before disease becomes overwhelming.

What fungicide kills anthracnose?

There isn't one universal fungicide recommendation for every case of anthracnose.

The correct product depends on the host plant, fungal disease, application timing and current Australian registration and label directions.

Never assume that a general-purpose fungicide is registered for anthracnose on your particular plant.

Can I use Lime Sulphur for anthracnose?

Don't make that assumption from the words “fungicide” or “broad spectrum” alone.

The current Dr Greenthumbs product information for Kendon Lime Sulphur specifically identifies uses including powdery mildew, rust and black spot.

For anthracnose, check the current product label for the exact plant and disease you need to treat before application.

Can you eat fruit affected by anthracnose?

Anthracnose can cause significant fruit deterioration and rot.

Fruit that is badly diseased, rotten or breaking down should be discarded.

Don't confuse “a plant disease isn't a human disease” with “rotting fruit is good to eat”. If in doubt about deteriorated produce, chuck it in the appropriate waste rather than taking chances.

Can anthracnose spread in wet weather?

Yes. Wet conditions can strongly favour many anthracnose diseases, and splashing water can help move fungal spores from infected material onto susceptible tissue.

Wet periods are a good time to increase monitoring.

Final Word: Beat Anthracnose by Changing the Conditions

The biggest mistake with anthracnose is treating it as nothing more than a spraying problem.

A bottle might form one part of a treatment program, but if diseased fruit is still lying beneath the tree, foliage stays wet all night and the canopy never sees moving air, you're leaving the welcome mat out for another outbreak.

Think bigger:

Identify it. Clean it up. Keep foliage drier. Improve airflow. Protect healthy growth. Treat only when the treatment fits the plant and disease.

That's how you shift from chasing spots around the garden to actually reducing disease pressure.

And if you're dealing with fungal problems beyond anthracnose, bookmark our Best Organic Fungicides in Australia guide for a practical breakdown of the different treatment options and when they make sense.

Happy growing.

Next Reads for Managing Fungal Disease in the Garden

Still seeing spots, lesions or recurring disease after wet weather? These guides will help you compare common fungal problems and reduce the conditions that keep them coming back.

• How to Get Rid of Powdery Mildew in Australia
• Best Organic Fungicide Australia Guide
• How to Correctly Water Your Garden
• Plant Nutrient Deficiency Guide

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