Avocado trees, with the scientific name Persea americana, are members of the family Lauraceae. The fruits are botanically considered large berries, containing single, large seeds. These trees originated in south-central Mexico and are cultivated in countries with tropical and Mediterranean climates. They are also prone to pest infestation, diseases and other problems that could lead them to the brink of death unless promptly addressed.
How to save a dying avocado tree
1. Identify the problem, and consult professionals if necessary.
Make a mental note of when you notice symptoms on your avocado tree, as it can be helpful when determining how to address the problem. Once you have identified the problem, you need to decide whether you can handle the situation yourself, or if you would like to seek the help of professionals. It could also be helpful to discuss the issue with fellow avocado tree growers, as they may be able to provide some guidance.
2. Protect the tree from sunburn.
If your avocado tree looks like it is dying and the leaves are turning black or brown, it could mean that the tree has severe sunburn. This damages the chlorophyll in the leaves and slows the rate of fruit production, eventually leading to death. Provide shade for your tree using cloth, or apply white latex paint on the branches to protect them from sunburn.
3. Protect the tree from fungal diseases.
Brownish leaves and branches that are starting to turn black could be an indicator of fungal disease. Common diseases among avocado trees include the following:
- Rosellinia root rot – Symptoms include white patches on the trunk or limbs, and purple growths near the soil. This is also known as white root rot.
- Oak root rot – These fungi look like a large group of yellow or brown mushrooms near the soil line. It is also known as Amarillo root rot.
- Common avocado root rot – Symptoms include brown leaf tips, black and rotting feeder roots, and dead branches on the treetops.
If your tree is infected with Rosellinia root rot, or white root rot, destroy it. Uproot it, along with all of the infected soil, to avoid the spread of infection to other trees.
Oak root rot and common avocado root rot are both treatable with fungicides. Apply these immediately and again in late spring and summer. Gypsum should be added to the first six inches of soil to prevent the diseases from spreading.
If the infection is severe, dry out the tree’s roots by pulling away the top six inches of soil to expose them. Make sure you do not damage the roots, and cover them with a cloth so they do not get sunburnt. Allow them to dry and then replace the soil with fresh, sandy soil.
4. Use wood mulch to encourage growth.
To help your avocado tree recover from diseases and boost its growth, place wood mulch around its base. The mulch discourages the development of bacterial or fungal infections and retains the soil’s moisture. Cover the root area near the base properly.
5. Take care not to overwater the tree.
Keep track of your watering schedule to avoid overwatering your tree. Overwatered avocado trees could develop root rot, which will likely lead to fungal and bacterial infections. By keeping track of your watering schedule, you will reduce the opportunity for fungal spores to thrive and multiply.
6. Check for excess minerals.
Excess minerals like chlorine and boron could promote bacterial and fungal growth. This happens most often in areas near the sea, or if the water source is saltwater. To avoid this, use rainwater or freshwater to irrigate around the base of the tree. If the tree does not get better, take a soil and water sample and have it tested by professionals so they can assess the situation and provide a suitable solution.
7. Ensure adequate drainage.
Excess water near the tree’s base makes the soil soggy and could lead to root rot since the roots are always soaking in water. The culprit is usually a poor drainage system. To fix this, dig drainage channels around your tree. You can also plant the tree on sloping land, or use pipes for channeling. Potted avocado plants should be in pots that have drainage holes at the bottom.
8. Fertilize correctly.
Avocado trees need a suitable mix of nutrients to grow well, and a nutrient imbalance may encourage the development of pathogens. Plant growth becomes stunted and the tree’s overall health may deteriorate. Provide avocado fertilizers in the correct proportions, and take soil samples to determine which nutrients are missing.
9. Use fungicides only as a final recourse.
If the above-mentioned measures were not sufficient to revive your dying avocado tree, you could try applying fungicides. Consult with specialists regarding the correct application. Fungicides, when used correctly, can eliminate pathogens and promote plant recovery and growth.
Avocado trees yield nutritious, edible fruits that are consumed by people the world over. However, they can be prone to problems and illness, and could die if not treated promptly. Save your dying avocado tree by ensuring that all of its needs have been adequately met to support its optimal health, and consult professionals when necessary for guidance on the proper measures to revive it.
Image: istockphoto.com / lukrecja