Blackberry hypoderma

Blackberry hypoderma is a fungal disease caused by the ascomycete Hypoderma rubi. This pathogen specifically targets the canes of blackberry plants, causing significant tissue damage and affecting the vascular system of the crop, which can lead to localized cell death and cane structural weakening.

The disease primarily affects various species of the Rubus genus, including commercial blackberry cultivars and wild varieties. The fungus infiltrates the bark and cortical tissues, drawing nutrients from the host and disrupting the physiological functions necessary for healthy growth and fruit production.

Symptoms typically manifest as dark, discolored spots on the canes. Over time, these spots become more pronounced, leading to bark cracking. Eventually, small, raised fungal fruiting bodies appear on the surface of the infected areas, serving as the primary source for spore dissemination during favorable conditions.

Development and spread of Hypoderma rubi are highly dependent on environmental factors, particularly high humidity and moderate temperatures. The fungus thrives in dense, poorly ventilated planting areas where moisture persists on the canes, facilitating the germination and movement of spores throughout the plantation.

The impact of this disease is reflected in reduced plant vigor, decreased fruit yield, and potential loss of entire canes. Effective management requires an integrated approach to cultural and chemical control strategies to keep the pathogen under control throughout the growing season:

• Prune and destroy all infected canes immediately to prevent further spread.
• Ensure proper spacing and trellis training to maximize airflow within the canopy.
• Apply recommended copper-based or systemic fungicides during dormant and active seasons.
• Minimize overhead irrigation to reduce moisture accumulation on the plant stems.