Phytophthora... A Deadly Fungus in Durian

Phytophthora... a deadly fungus in durian

Phytophthora infection is usually named after the visible symptoms it produces, such as root and stem rot (damage at the base of the durian trunk), fruit rot (damage to the durian fruit), or leaf blight (damage to the leaves), among others. Like other fungal pathogens, Phytophthora infection depends on the same 3 favorable conditions being present.

Root and stem rot from Phytophthora

Durian is a high-value economic crop, commanding a high price per kilogram, so durian growers tend to apply very intensive care, fertilizing continuously every month throughout the growing season. However, fertilizer residue building up in the soil raises soil acidity (pH below 5), and when this combines with humidity levels favorable for growth, it allows Phytophthora to thrive readily in such orchards.

A comprehensive approach to managing root and stem rot disease:

Correct soil acidity by applying lime or dolomite to raise soil pH, aiming for a range of 6-7 (the application rate per tree should follow the same reference used for fertilizer application).

Improve orchard drainage so water does not pool anywhere, since standing water collects the fertilizer that washes into it and also creates excess humidity — conditions that favor disease development.

Use Magic Humic Plus Fulvic at 300-500 grams per [tank of] water.