Latex eruption

Latex eruption is a physiological disorder, frequently categorized under the edema complex, affecting plants with high internal latex pressure. It is not caused by bacteria or fungi but by an internal imbalance where the plant's vascular system experiences excessive hydrostatic pressure, forcing latex to breach the tissue surfaces.

The primary crop affected by this condition is poinsettia (Euphorbia pulcherrima). Due to its complex internal system of laticifers, this plant is highly susceptible to tissue rupture when environmental conditions prevent proper transpiration, causing the milky sap to exude and harden on the leaf surface.

Symptoms appear as small, raised bumps or corky spots on the leaves. Over time, these spots may turn brown or tan as the exuded latex oxidizes and dries out. While these lesions are localized, they can lead to leaf distortion and significant aesthetic damage, which is detrimental to the marketability of ornamental crops.

The development of latex eruption is strictly correlated with environmental stress. It occurs most frequently when root uptake of water exceeds the rate of transpiration. High humidity, poor airflow, and cool or overcast weather conditions significantly contribute to the onset of this disorder, preventing the plant from regulating its water levels efficiently.

• Maintain optimal greenhouse airflow and ventilation.
• Monitor substrate moisture to prevent overwatering.
• Manage humidity levels to encourage constant transpiration.
• Avoid sudden temperature fluctuations during the growing cycle.

Prevention involves strictly managing the growing environment. Since latex eruption is a physical response to stress, chemical treatments are ineffective. Growers must ensure that the humidity, watering, and temperature are balanced to prevent the buildup of internal pressure that causes these damaging leaf eruptions.