Fact sheet: Hazelnut disease – Kernel defects

Maintaining orchard health is critical to ensuring a productive and profitable Australian hazelnut industry. This fact sheet is part of a series developed to help growers identify, understand and manage key diseases that can impact hazelnut production. It provides practical information on symptoms, disease spread and management strategies to support informed decision-making in the orchard.

Kernel defects can reduce nut quality, lower market value and lead to crop losses, even when external symptoms are not immediately visible. Most defects are associated with fungal infections, particularly Diaporthe species, although Aspergillus, Alternaria and Fusarium can also be involved. This fact sheet explains the causes of kernel defects, factors that increase risk, and the orchard and post-harvest practices that can help maintain kernel quality and minimise losses.

Related resources:

Fact sheet: Hazelnut disease – Hazelnut mosaic
Fact sheet: Hazelnut disease – Tree decline and branch dieback