Quick Czech! Durian, the brick orange dot is fungus or algae.

Algal Leaf Spot in Durian is not a fungus, but a species of green algae that has developed itself into a plant parasite. It is often plagued by high humidity, thickets, or during the rainy season. It is not a disease that causes immediate death, but a severe outbreak can cause a decrease in photosynthetic leaves, fall leaves, and affect the integrity of the Durian tree.

Details of symptoms and treatment are as follows.

Symptoms of algae spot disease

It can be clearly observed on leaves, especially old leaves, in the lower bushes or light parts.

- Early stage: A small, yellowish-green or greenish-gray round wound spot occurs on the upper leaf surface.

- Expansion stage: The wound point is slowly enlarged; the surface of the wound will be fluffy, velvet-like, or powder-like, rusty (reddish-orange or brick-brown), a part of the reproductive structure (spores) of the algae.

- Severe stage: The wound expands into a collide, causing the dry part of the leaf to die, becoming gray brown. If severe, the leaves will yellow and fall prematurely. In some cases, they may spread on the branches, causing the bark to break and deteriorate.

Prevention and treatment

Management of algae spot leaf disease requires emphasis on both adjusting the environment to reduce humidity, and the proper use of controlled chemicals.

1. District management (protection)

- Shrub Trim: Small branches, diseased branches, or overlapping branches should be pruned to make the bushes clear, sunlight reach the ground, and provide convenient ventilation, which will reduce the moisture accumulation that is the main cause of algae growth.

- Fertilizer management: Avoid putting nitrogen fertilizer too high during the rainy season because it will cause the durian to break the leaves tightly and dunderlying. Supplemental nutrients should be supplemented to strengthen the leaf walls.

2.Use of chemical anti-removal (treatment)

Because it is caused by algae, not fungi, the most effective chemicals are a particular group of copper compounds or algae removal agents.

- Recommended chemicals:

- Copper oxychloride

- Copper hydroxide

- Copper sulfate

- Method of use: Spray all over the bushes, highlighting the old leaves and shrubs below the outbreak. Respray every 7-10 days if the outbreak is still found during the rainy season.

* * Cautions for the use of copper group substances:

- Avoid spraying while the durian is splitting the young leaves because it can cause the young leaves to burn or disrupt growth.

- Avoid spraying during hot or too sunny weather.

- Copper should not be mixed with other strong acidic chemicals or certain leaf / hormonal fertilizers because of a toxic chemical reaction to plants.

# Agriculture # Durian disease # Durian algae spot leaves # Rookie planted durian # Copper substance