Dry root rot

Dry root rot is a severe fungal disease complex predominantly affecting citrus orchards. It is primarily caused by soil-borne fungi, most notably Fusarium solani, which often works in conjunction with other stress-inducing pathogens. The disease targets the root system, destroying the vascular tissues and preventing the plant from absorbing essential water and nutrients effectively.

This pathology is widely observed in citrus species, including oranges, lemons, and grapefruits. However, the disease can also manifest in various woody shrubs and ornamental plants under favorable conditions. The fungi inhabit the soil, waiting for the host to experience stress before infiltrating the root tissues through wounds or physical root damage.

The characteristic symptoms of dry root rot differ from wet rot because the decayed roots appear dry, brittle, and crumbly rather than slimy or malodorous. Above ground, the symptoms include yellowing of leaves, leaf drop, and sudden wilting of branches. Eventually, the bark at the rootstock-scion union may crack, and the plant will exhibit signs of severe physiological decline.

The development of the disease is highly correlated with environmental stress factors. Periods of extreme heat, drought, or soil water saturation are primary triggers. Soil compaction, poor aeration, and damage caused by nematodes or improper cultural practices further exacerbate the susceptibility of trees to the fungal complex, allowing it to spread rapidly across the orchard.

Integrated management is essential for long-term control. Prevention starts with the use of pathogen-free nursery stock and the selection of disease-resistant rootstocks. Maintaining soil health through proper fertilization, adequate drainage, and avoiding root damage during cultivation is crucial. In severe cases, systemic fungicides may be applied, but sanitation—removing and destroying affected plants—remains the most effective strategy to prevent spread.