FERTILISER GUIDELINES FOR THE WINE INDUSTRY

FIGURE 23: Zndeficiency can lead to small, apical leaves, short internodia (witches’ broom), enlarged petiole sinuses and small, seedless berries.

5

TABLE 16: Norms for the Zn-contents (mg.kg -1 ) of leaf blades and petioles of grapevines.

Fruit set

Leaf blade

Petiole

Deficiency Sufficient

High Toxic NA NA

Deficiency Sufficient High Toxic

<15

>30

<15

25-100 NA NA

Veraison

Leaf blade

Petiole

Deficiency Sufficient

High Toxic NA NA

Deficiency Sufficient High Toxic

<15

>30

<15

>25

NA NA

NA – not available.

65