Why are there Brown Spots on Avocado Leaves (Ways to Fix them)

by Becky Decker and Anita Shan · June 29, 2024

I was excited to plant an avocado tree in my garden because after some time I will enjoy homegrown avocados. However, I noticed brown spots on the leaves and was concerned about what was the reason behind them. But I didn’t want to let my excitement go to waste, so I decided to eliminate this problem as soon as possible —and I succeeded.

If you’re reading this article, you’re probably curious about what causes brown spots on avocado leaves. Don’t worry; I’ve outlined every possible reason for these spots and provided solutions for each one. Let’s work together to save our avocado tree!

Quick takeaways:

Having brown spots on avocado leaves is not a good sign because it indicates there is some problem in the tree.
The fruit of the plant is a type of berry having one large round seed with two cotyledons.

What is an avocado?

The avocado appearance is a vivid green fruit with a vast pit with a dark, leathery skin. Talking about its skin which is thinner than the skin of an apple but it’s possible to get text rough and woody.

The fruit of the plant is a type of berry having one large round seed with two cotyledons. They are considered the primary ingredient in guacamole which is a common ingredient in Mexican food.

It is low sugary fruit and some varieties contain high levels of vitamin A, Thiamin, and riboflavin. Most importantly the flesh of avocado does have as much as 25 percent of unsaturated oil.

The avocados are full of calories and nutrients. Some details of serving recommendation:

An average ⅓ of avocado i.e. 50 grams of 1.71 ounces.
They used to grow in large sizes or spread well.
The shape of avocado is egg-shaped or elliptic leaves containing a size between 10 and 30 cm in length.
They used to grow in tiny, greenish flowers having large inflorescences but didn’t have any petals.

The reason behind avocado leaves turning brown:

There might be a situation in which leaves get burned due to myriad causes from sunlight. You can find trees with leaves turning brown around tips and edges that are caused by an accumulation of soil salts.

The brown spot on avocado leaves can also be because of dry conditions or lack of irrigation which will cause the burning of avocado leaves. The following are some more possible cause that causes the plant leaves to get dehydrated:

Not enough watering:

The avocado tree tends to thrive best in USDA hardiness zones 8-11 which ranges between subtropical and tropical.
Avocado trees need to give water because the trees get exposed to heat all year round and if they are not watered corrected leaves will start to develop brown leaves because the roots of the plant don’t get to hold water which nourishes the cool of the leaves.
It’s actually easy to determine when the avocado’s leaf is suffering from water insufficiency because the sufficient water content in the top 4 inches of the soil is clear and hydrated which helps in cooling and moistening all areas of the plant.
In case of too dry and hot weather, root watering and transpiration can’t efficiently keep the plant and leaves cool because this causes avocado trees’ leaves to get dry or curl which results in brown and falling leaves.
You need to provide the trees with fifty gallons of water for each pound of fruit.

Why are there Brown Spots on Avocado Leaves (Ways to Fix them)

Sunburn:

The brown spots on avocado leaves can be caused by sunlight which makes them dry up.
The leaves get dry and have a damaged appearance near the end of the trees.
The leaf burning damages leaves to drop off the tree way earlier than the average time of dormancy.
It’s not just because of hot sunburn as it is possible to occur when the clouds are in the sky and the temperature gets warm or cool.

Dry air:

The avocado belongs to a humidity tropical region where the air humidity lies in the 70-80 percent range and gets exceeded.
Humidity may decrease during the summer heat which is at or below 30% in the house.
If the air is dry, evapotranspiration grows in which the loss of water in leaf cells takes place. During this time, the avocado starts to lose water more rapidly and the cells begin to die causing browning of the leaves.

Frost:

Frosting results in destroying avocado leaves that cause leaves to turn brown.
In case the plant has brown spots on the avocado leaves due to frost which can be found when leaves begin to curl and change color.
You are required not to the trees be exposed if there is a chance for the temperature to drop below 25℉.

Zinc deficiency:

Zinc deficiency happens more commonly than other deficiencies to avocado trees.
The zinc deficiency causes small brown spots on avocado leaves with discoloration on the leaf margins on the plant leaves resulting in more distortion.
To cure the leaves from brown spots you need kelp extract or a spray for foliage that will help to overcome the deficiency.

Nitrogen deficiency:

There is a possibility of an increase in moisture content in soil which causes the loss of nutrients from the trees.
If you have yellow leaves and tiny darker brown spots are straight symptoms of nitrogen deficiency.
The nitrogen deficiency condition is treated by watering the avocado trees at a moderate rate and applying nitrogen-rich fertilizers.

Salt accumulation:

The leaf’s color changes when sodium salts and chloride leaves rise due to salt accumulation which is caused because of irrigation.
The perfect chloride concentration ranges from 80 to 100 parts of a million.
The avocado leaves get affected when the chloride leaves are higher than 75 parts of a million.

Edema:

Edema is a kind of disease that causes dark spots on avocado leaves.
The leaves will appear smudge-like crust and swollen, corky veins alongside brown spots.
This is caused because the soil of the tree holds plenty of water to nourish the roots but unfortunately, the humidity is too high which allows the water to evaporate completely out of the leaves.

Iron deficiency:

If the tree is suffering from a lack of iron you can observe it in soil using acidic pH which is common to have in avocado trees because it will suffer burning at the tip.
The leaves dropping and slight changes in the veins changing color will be there if the plant is suffering from iron deficiency.
The avocado tree and orange tree used to grow at home and tropical houseplants

Ways to fix Brown Spots on Avocado Leaves:

It’s common to see around 10% of leaves change color but if the percentage is more significant then it is unnecessary to take action hence there is no reason to cut the leaf of a tree that has a brown tip. You need to know which disease the tree is suffering and treat them accordingly. Do you know the damaged leaves won’t change color when the humidity rises and the new leaves will not change color to brown. Don’t think providing excess moisture will not fix brown leaves but will prevent further damage.

Algal leaf spot:

You can identify the disease for algal leaf spots when the leaves have green, yellowish, or red-orange spots that are visible within a mass of the leaf.
You can find algal leaf spot disease in regions that produce tropical avocados.
The common place you find avocado plants growing in the southern region of Florida.
The signs when the plant is suffering from an algal leaf spot are first visible on the upper surface of the leaf when it gets yellowish, green, or spots that are rusty.
There are some conditions when it expands into branches and twigs or combines to form a giant blob of damaged tissue.
The common symptoms can occur between the autumn and summer months.

Leaf spot treatment:

In case the younger or crucial landscaping species get affected by spots where treating leaf avocados is simple.
The spots don’t disappear after treatment but there is a way to stop the growth of new areas by shrinking in size using spray copper spray.

Plant fungal diseases:

The avocado leaf having brown spots is also possible due to fungal infection. The following are three of the most common fungal disease that affects the plant:

The fungal disease Anthracnose causes dark brown leaves which burn due to sun and extreme lead drops.
The plant suffering from downy mildew initially appears yellow, having grayish-looking substances. You will get to see Spot brown after which the entire leaf will fall off.
The plant suffering from Alternaria leaf blight will start to have tiny small brown streaks on avocado leaves which have an elongated yellowish edge and result in rotting the entire leaf

Reasons for fungal infections:

The following are some possible reasons behind when your plant can suffer from a fungal disease:

When the avocado plant is overwatered it is a significant factor in fungal decay.
If the tree has an inadequacy of drainage out of the soil then the pot may cause fungal spots on leaves of avocado leaves. Make sure the bank has drainage holes with proper dimensions which will help in removing excess water after every water use.
When the soil is too squishy and prone to retaining moisture it will cause root and plant decay. Ensure to use aerated soil that helps water to escape from it.
The fungi prefer to have humid, hot, and cramped environments so don’t place the plants too close for good air circulation.

Prevent brown spots on leaves:

You can prevent the burning of avocado trees when you provide the tree with regular well-drained irrigation.
The avocado tree is tropical by nature, so it is well adapted to have long rains that are heavy, and long, not shallow, short shallow ones.
In case the backyard becomes dehydrated, there is a need for mulching with pine needles and leaves that help improve water retention within the soil.
The compost helps in adding organic matter and nutrients to the soil by increasing 1% of soil richness by taking in 20000 more gallons of water per acre.
The perfect way to eliminate the salt is by using deep watering or vinegar as a remedy.
Leaves having brown spots also can be because of excess use of fertilization. Always use according to the directions mentioned on the label.
You can apply compost once every 1-2 months and mulch once every 6-12 months.
In case the frost becomes thicker or more prolonged, just cover the avocado plant using plastic sheets or keep them indoors until the frost gets over.
The avocado tree which gets mature boasts a large canopy that extends in every direction. The roots of the plant grow far to the shelter. So in case of watering the seeds you need to sprinkle water around the edge of the canopy but don’t direct water to the tree’s trunk.

How to reduce salt in the soil

The following are steps that will help in decreasing the amount of salt accumulated in the soil.

Deep watering:

To make sure of consistent education, you need to place the water hose near the tree’s roots and make it run. The tree having adequate water will help in the building of chloride. The trees originated in tropical regions. That is why they like sandy soil with a good amount of water.
Here sand is typically acidic, but the clay tends to be alkaline whereas the avocado trees like mild acidic soil pH of 5.0-7.0. Hence, grows based on sandy soil
In the case of having soil, that is well drained, the most perfect method to decrease the building of chloride is by providing the sand with an extra amount of water, which will reduce the appearance of brown leaves on the tree.

Vinegar:

You can also reduce the salt in the soil by adding 1 to 2 tablespoons of vinegar in a gallon of water and starting the water tree, which is turning brown.
Try using a reverse osmosis filter, which is like an electric motor and results in boosting the pressure at the salt of RO. When you use this method, the water begins to flow throughout the semipermeable RO membrane due to which the dissolved salt gets eliminated from the rejected stem

Ways to find Avocado is good or bad:

The avocado is ripe until it is picked from the tree after which the process happens quickly. When they are ripped you will have a narrow window just a few days before the fruit starts getting spoiled.

In case you want to find out how to determine if the avocado is getting rotting and is not good for eating. The following are signs that will tell you whether the plant has gone bad or not:

1. Overly soft with dented skin:

To check the ripeness, use the palm of your hand and gently squeeze the avocado. Make sure not to press the fruit with your fingers which will result in bruising the flesh.
In case the avocado is very firm, it means it is under-ripe. If it gives slightly, it means it is likely ripe, which you can eat.
When you find the squeezing leaves an indentation it means the avocado is too ripe, which is good to eat by mashing.
Pressing the leaves creates a large dent, and the fruit feels mushy. It means the fruit is overrated or can be spoiled.

Note:

After squeezing the avocado, gently in the palm of your hand, which left a large indentation the place you pressed means the fruit is over ripped that you can’t eat.

2. Blackened skin:

Some types of avocados have different skin color changes when they are ripped.
The hass variety Are which is eaten by 80% trusted sources worldwide.
Hass avocados do have bumpy bright green skin when they are not fully ripe.
After some progress, the skin changes to dark green or brown, which means they are ripped.
In case the skin looks nearly black and is mushy when you touch it, which means it is overripe or spoiled.
The avocado varieties such as the Zutano and FuerteTrusted Source maintain the green color which does not change according to their ripe condition. So here you need to use other methods such as feeling for firmness to check whether they are good to eat or not.

Note:

Most of the avocado varieties change to black skin when they are overrated or rotten whereas the other varieties remain green in color.

3. Dark, stringy flesh:

When you cut an avocado it is easy to determine whether the avocado is good or bad. Of course, why it shouldn’t be as it is the only option when you have bought it from the market?
The avocados are ready to eat and have light green flesh; the Rotten avocado has brown or black spots.
There is the possibility of having an isolated brown spot due to bruising which you can cut away.
The avocado may have dark streaks in the flesh when they are harvested from a young tree so it doesn’t mean it is rotten. In case the fruit looks good and tastes fine it means it is good to eat.