Avocado (Persea americana) is a beloved fruit known for its buttery green flesh, unique shape, and potassium content. Avocado trees are one of the most rewarding fruit trees to grow in warmer climates as they love getting full sun, but starting from scratch with seeds involves waiting for over a decade to see fruit. In this time, from planting to harvest, avocado trees are vulnerable to a range of fungal and insect diseases, as well as individual avocado tree problems that are difficult to ignore.
Due to the work and time involved in growing a healthy tree, it’s essential to spot warning signs of issues affecting your avocado tree and know how to resolve them for the sake of your future harvest.
Suppose you’re dealing with avocado plant leaves curling or lesions on your tree trunk or are simply curious about what could occur in the new avocado plant you’ve planted in your Florida garden. This article addresses common avocado tree problems and how to resolve them to save your avocado tree on its way to harvest.
Common Problems with Avocado Trees
When growing avocados, problems associated with the variety of avocados to plant are important. For example, Panama Dwarf is not resistant to the cold and needs to be overwintered inside each winter, unlike the cold hardy variety Zutano. Other superior types include Reed, Fuerte, Hass, and Pinkerton.
The most common variety of avocado is Hass, and issues addressed here generally reference this variety.
Avocado trees are shallow-rooted with feeder roots within the top six inches of soil and prefer direct sunlight and well-drained soil to avoid becoming drenched. Not letting your soil become drenched is one avoidable issue when growing your tree.
Avocado Plant Leaves Curling or Wilting
If you start your avocado growing journey by growing your plant indoors, it is subject to other issues that houseplants may face, like yellowing leaves. The best way to grow fruit trees in pots or containers like avocados is to ensure the proper amount of water.
It may be challenging to know when watering your plant if you’ve given your avocado plant enough water, but overwatering leads to root rot.
Overwatered roots, surprisingly, prevent your leaves from getting the necessary water and result in your avocado plant leaves turning brown or avocado plant leaves curling downward.
One thought to resolve this may be to begin fertilizing your plant; however, the purpose of fertilizer is to provide plants with nutrients they may miss in the soil. If your roots are struggling to absorb due to being drenched, this will not cure your plant.
Another symptom of poor root health is new leaves on your plant that are small or too few. Because of a flooded root system, your plant does not have enough nutrients to form these new growers at the proper size.
Fix drenched roots by resolving drainage issues, but replanting may be ideal if the flooding is severe. Avocado transplanting is much easier while the tree or plant is young, within the first year. The same applies to an avocado tree in container or pot.
Avocado Trees Affected by Sunblotch
Sunblotch is a severe and incurable disease that affects avocado trees. Despite its name, the sun does not directly harm avocado trees in this way. Sunblotch comes from submicroscopic particles that alter the development and growth of infected plants and affect coloring, resulting in avocado tree leaves turning yellow.
Trees may show some or none of the above symptoms, and if trees do not show any signs, they are known as symptomless carriers. Trees with visible sunblotch symptoms often have reduced yields, and if trees that do not show symptoms are producing lower yields, it may be a sign of the infection.
There is no cure for sunblotch, so prevention is your best bet for avoiding it. Careful stock selection and resistance in plants aids in keeping sunblotch out of your garden. If you have sunblotched trees, consider that most cuttings and seeds from diseased plants are also infected.
Avocado Branch Canker Disease
Cankers or areas of dead tissue occur on twigs, branches, and trunks of avocado trees. Caused by complex fungal pathogens, they enter your tree through wounds on the bark surface left by frost damage or from unhealed areas if you prune your tree.
Due to cankers targeting branches and trunks, your fruit is not directly affected; however, spores from the soil surface affect your fruit through splashing during rainy weather. To prevent this, create a barrier between your soil and fruit with mulch.
Avocado Tree Leaves Turning Brown from Anthracnose
Anthracnose is a common fungal disease of various trees, resulting in the curling of leaf tips and brown spots forming on leaves. While anthracnose does not pose a significant threat to the health of your yard tree and may not always require treatment, in the case of affecting your avocado tree, anthracnose is serious.
Fruits from diseased trees may appear fine but develop blemishes from latent infections as the anti-fungal compounds in unripe fruit skins diminish as the fruit ripens. The fungus creates dark brown lesions that grow on the fruit skin and into the pulp, causing rot. Sometimes you don’t discover the problem until after picking avocados and trying to eat them.
Avocado cultivars differ in their susceptibility to anthracnose, so choosing a variety of avocados suited to your environment helps avoid infection.
Avocado Tree Problems from Phytophthora cinnamomi
This pathogen of water mold is one of the most invasive species worldwide and, once infected in plants through the root system, causes a condition more commonly known as root rot. When you plant avocado tree in soil outside, root rot is always a possibility.
A 1960 study in California found a correlation between avocado root rot specific to avocado trees in areas with poor soil drainage.
Root rot is the leading cause of damage to avocado trees, and in response to root rot, farmers developed resistant avocados to minimize the damage from this condition. Trees affected with root rot generally die or become unproductive within three to five years.
There is no known cure for P. cinnamomi, so prevention is your best defense. Before planting your tree, ensure your soil site has good drainage with no runoff from any potentially infected trees.
Ensure that your seedling comes from a certified stock that may have resistance to root rot. Fungicides won’t cure root rot, though they help control the disease to make your tree more resilient.
Avocado Tree Leaves Turning Brown from Pests
Not every threat to your avocado plant is a pathogen. Another concern may be an infestation of pests such as the Western Avocado Leafroller damaging your tree.
These pests affect trees mainly in California and can cause severe fruit damage. Their eggs can be found on the upper side of leaves and resemble white patches on leaves once hatched.
Young larvae chew on the surface of avocado leaves and leave a skeleton of leaf veins, whereas mature caterpillars may eat the entire leaf. Larvae may also feed on fruit skin and can result in downgrading or culling of fruit.
While there are natural solutions to these pests, such as birds and spiders, insecticide like Bacillus thuringiensis (Bt) is commercially available.
We hope after reading about common avocado tree problems, you take action when you see your avocado tree leaves turning brown and if this article was insightful to you, please share it with fellow avocado enthusiasts on Facebook and Pinterest.