Borro sec

Borro sec (caused by the fungus Cryptosporiopsis tarraconensis) is a serious infectious disease affecting mainly hazelnut. This pathogen belongs to a group of fungal diseases capable of causing necrotic processes in the plant's wood and bark, which leads to a gradual decline in the productivity of orchards.

The pathogen affects almost all above-ground organs of the hazelnut, but it is most dangerous for branches and trunks. During its lifecycle, the fungus penetrates plant tissues and destroys their structure, which disrupts normal nutrient flow. Ultimately, this leads to the drying out of individual branches or the complete death of the plant if not properly controlled.

The main symptoms of infection include the appearance of specific sunken spots or necrotic zones on the bark. In affected areas, the bark may crack, eventually turn dark, and spore-producing structures often form underneath. Leaves on infected branches turn yellow and drop prematurely, with noticeable growth retardation and dieback of the shoot tips.

The development of Cryptosporiopsis tarraconensis is favored by high humidity, moderate temperatures, and the presence of mechanical wounds on the bark, through which the infection easily enters. Spores are dispersed by wind, rain splashes, or insects that damage the wood, as well as through infected planting material.

The harm caused by the disease includes reduced yields and lower quality of nuts, as well as the degradation of plantations. To combat the pathogen, a complex of measures is used:

• removal and burning of infected branches;
• disinfection of cut sites with horticultural wax or copper-based preparations;
• regular preventive spraying with fungicides;
• maintaining high agronomic standards to boost tree immunity.