Blueberry

Vaccinium spp.

1. Identification and origin

The blueberry (Vaccinium spp.) belongs to the Ericaceae family and includes several species of agricultural interest, notably Vaccinium corymbosum L. (highbush blueberry), Vaccinium angustifolium Aiton (lowbush blueberry) and Vaccinium myrtillus L. (European wild bilberry). The origin of the group lies in temperate and cold regions of the Northern Hemisphere, with high natural diversity in North America. Modern domestication intensified in the 20th century, especially in the United States, subsequently expanding to Europe, South America and Oceania.

2. Economic importance

The blueberry is valued for fresh, frozen and processed consumption (juices, jams, nutraceutical products). The global market has grown rapidly due to its high content of antioxidants, fibre and bioactive compounds. In Portugal, the crop has gained ground on small and medium farms, integrating intensive systems with high commercial value. Internationally, the main producers include the United States, Canada, Peru, Chile, Spain and Poland.

3. Botanical characterization

A perennial shrub, of variable size depending on the species, able to reach 0.3–2.5 m in height. The leaves are simple, alternate, with entire margins. The flowers are bell‑shaped, generally white or pink, gathered in clusters. The fruit is a dark‑blue berry, rich in anthocyanins. The root system is shallow, fine and highly dependent on ericoid mycorrhizae. The cultivated species display great variability in vigour, growth habit, flowering time and fruit size.

4. Soil and climate requirements

The blueberry adapts to humid temperate climates, with a chilling‑hour requirement that varies according to the species and cultivar. It prefers acidic soils (pH 4.0–5.5), well‑drained, rich in organic matter and with good water‑retention capacity. It is sensitive to waterlogging and salinity. It requires regular irrigation, especially during fruit filling, and benefits from organic cover (mulching) to maintain moisture and protect the shallow roots.

5. Main pests

• Spotted‑wing drosophila (Drosophila suzukii): oviposition in fruits and subsequent rots
• Aphids (Aphididae): sap sucking and transmission of viral diseases
• Scale insects (Coccoidea): weakening of branches and production of honeydew
• Mites (Tetranychidae): chlorosis and reduction of photosynthesis
• Nematodes (Pratylenchus spp.): root damage and decline in vigour

6. Main diseases

• Stem canker (Botryosphaeria spp.): death of branches and reduction of production
• Grey mould (Botrytis cinerea): infection of flowers and fruits in humid conditions
• Anthracnose (Colletotrichum spp.): fruit rots and premature drop
• Phytophthora (Phytophthora cinnamomi): root rot and plant death
• Powdery mildew (Microsphaera vaccinii): white coating on the leaves and reduction of vigour

7. General crop management

Management includes the choice of cultivars adapted to the local climate and chilling requirements, establishment in well‑drained acidic soils, the use of organic matter and mulching, frequent irrigation but without waterlogging and annual pruning to renew the productive structure. Weed control is essential due to the shallow root system. Monitoring of Drosophila suzukii and fungal diseases is fundamental during humid periods. Harvesting is carried out manually, in several passes, when the fruits reach a uniform blue colour.

Bibliographic references

• EPPO Global Database – Vaccinium spp.
• CABI Crop Protection Compendium – Vaccinium spp.
• Retamales, J. B., & Hancock, J. F. (2012). Blueberries. CABI Publishing.
• Lobos, G. A., & Hancock, J. F. (2015). Breeding blueberries for a changing global environment. Journal of the American Society for Horticultural Science, 140(2), 89–100.
• Scalzo, J., Politi, A., Pellegrini, N., Mezzetti, B., & Battino, M. (2005). Plant genotype affects total antioxidant capacity and phenolic contents in fruit. Nutrition, 21(2), 207–213.