Black raspberry

Rubus occidentalis

1. Identification and origin

The black raspberry (Rubus occidentalis L.), belonging to the Rosaceae family, is native to North America, where it occurs naturally from the Great Lakes regions to the Appalachians and the Northeastern United States. The genus Rubus is extremely diverse, but R. occidentalis stands out as the main species producing true black raspberry, distinct from red raspberries (Rubus idaeus) and interspecies hybrids. The species has been widely used in breeding programmes due to its disease resistance and high content of bioactive compounds.

2. Economic importance

The black raspberry is valued for its intense flavour, dark colour rich in anthocyanins and high antioxidant value. It is used for fresh consumption, freezing, jams, juices and nutraceutical products. Commercial production is more limited than that of red raspberry, but has grown in specialised markets in the USA, Canada and Europe, where it is appreciated as a premium fruit.

3. Botanical characterisation

A perennial shrub with a long-lasting root system and biennial aerial canes, similar to those of R. idaeus, but generally more arched and with a higher density of prickles. The leaves are compound, with 3–5 oval leaflets and serrated margins. The flowers are white and hermaphrodite. The fruit is an aggregate of drupelets that separates from the receptacle at the moment of harvest, forming a hollow fruit, of bright black colour when ripe.

4. Soil and climate requirements

It prefers cool temperate climates, with winters cold enough to fulfil dormancy. It tolerates heat better than R. idaeus, but is sensitive to prolonged drought. It requires deep, well-drained soils, rich in organic matter and with a pH between 5.5 and 6.5. It is very sensitive to waterlogging and benefits from regular and controlled irrigation.

5. Main pests

• Spotted-wing drosophila (Drosophila suzukii): perforations and deterioration of the fruits.
• Mites (Tetranychus urticae): chlorosis and loss of vigour.
• Aphids (Amphorophora spp.): leaf curling and virus transmission.
• Weevils (Otiorhynchus spp.): root damage and defoliation.
• Fruit fly (Ceratitis capitata): occasional attacks in Mediterranean regions.

6. Main diseases

• Grey mould (Botrytis cinerea): the main disease in raspberries, affecting flowers and fruits.
• Cane blight (Didymella applanata): necroses and death of canes.
• Anthracnose (Elsinoë veneta): lesions on canes and leaves, common in R. occidentalis.
• Root rot (Phytophthora fragariae var. rubi): root rot in poorly drained soils.
• Viruses (RBDV, RLMV): mosaics, chlorosis and reduced productivity.

7. General crop management

This includes choosing varieties adapted to the local climate, installation in well-drained soils, training on a trellis system, annual pruning appropriate to the biennial cycle of the canes, frequent but controlled irrigation, balanced fertilisation, monitoring of pests and diseases, and careful harvesting to preserve the integrity of the fruits. Canopy ventilation and humidity control are essential to reduce fungal diseases.

Bibliographic references

• EPPO Global Database. Rubus occidentalis – pests and diseases.
• CABI Invasive Species Compendium. Rubus occidentalis – datasheets.
• Finn, C. E. (2008). Black raspberries. In: G. R. Beecher (Ed.), Berry Fruit: Value‑Added Products for Health Promotion (pp. 177–196). CRC Press.
• Weber, C. A. (2003). Black raspberry breeding and genetics. Acta Horticulturae, 626, 83–90.
• Dossett, M., & Finn, C. E. (2010). Genetic improvement of black raspberry. Journal of the American Society for Horticultural Science, 135, 35–43.