Guidelines for the preparation of table grapes in SA for export 2025/2026_ND

Vigour norms

The following norms apply to vigour evaluation between véraison and harvest. The amount of sunlight penetrating the trellis and canopy should be estimated at midday, when the sun is at its highest point. Poor vigour Final shoot length 50–80 cm.

Average shoot diameter is less than 8 mm. Short internodes (less than 5 cm on average). Shoot tips are poorly hardened off. No active growth tips after 10 mm berry diameter. Light green leaves.

The shade pattern on the ground beneath the trellis consists of more than 50% sun patches. Determine whether poor vigour is due to physical or chemical soil limitations, excessive or insufficient soil moisture, or soil-borne pests such as phylloxera, nematodes, or margarodes. Moderate vigour Final shoot length 80–100 cm. Average shoot diameter 10–12 mm No active growth tip at véraison. Ideal vigour Final shoot length 110–150 cm. 20%–30% active growth tips at véraison. 10–12 leaves per bunch. The shade pattern on the ground beneath the trellis consists of 20% sun patches. Only light topping and cutting back are required. High vigour Shoots longer than 150 cm. More than 50% active growth tips after véraison. Growth tips curl strongly, and shoots have a strong tendril and long petioles. The third tendril from the top can be pulled past the growth tip. Yellow leaves resulting from insufficient light. Black and red grapes colour poorly. Tendency to sparse bunches. Poor fertility. Risk of decay. The shade pattern on the ground beneath the trellis consists of less than 20% sun patches. Topping is needed 2–3 times during the season.

SATI GUIDELINES FOR THE PREPARATION OF TABLE GRAPES IN SOUTH AFRICA FOR EXPORT 19