Magnesium deficiency-Table Grape

Change crop

Nutrients

Grapevines - Necrosis

Symptoms
With severe magnesium deficiency the leaf margins show necrosis, dry and drop off prematurely. Especially older leaves are concerned.

Reasons
Magnesium deficiency High applications of K or ammonium can induce Mg deficiency symptoms even on soils that contain enough Mg.

Grapevines - Necrosis

Symptoms
Magnesium deficiency causes interveinal yellowing or reddening (red vine) on older leaves first. Discoloration starts on the leaf margin and proceeds towards the petiole attachment point. Leaf veins and a line along them remain green. Furthermore necrotic areas develop in the discolored zones.

Reasons
Magnesium deficiency High applications of K or ammonium can induce Mg deficiency symptoms even on soils that contain enough Mg.

Grapevines - Necrosis

Symptoms
Magnesium deficiency causes interveinal yellowing or reddening (red vine) on older leaves first. Discoloration starts on the leaf margin and proceeds towards the petiole attachment point. Leaf veins and an adjacent zone along them remain green, producing a characteristic palmate vein banding. At advanced stages, leaf margins turn necrotic brown.

Reasons
Magnesium deficiency Magnesium deficiency usually occurs in soils of low pH and where potassium is abundant. Symptoms can be easily confused with those of leaf roll virus.

Grapevines - Necrosis

Symptoms
Magnesium deficiency on grapes causes a disease called stalk necrosis or tendrill atrophy. Stalks of grapes show brown necrotic areas. Grapes of injured stalks are not sufficiently supplied and dry out.

Reasons
Magnesium deficiency on fruits This physiological disorder is caused by Mg undersupply or an imbalance of K/Ca+Mg.

Grapevines - Necrosis

Symptoms
Lack of magnesium can result in disorders such as bunch stem necrosis. It starts as a hollow necrosis on the stalk of the berries, later the grape skin breaks down and pulp becomes watery. The disease is also known as Water Berry, Stiellähme, Shanking, Palo negro, Dessèchement de la Rafle).

Reasons
Magnesium deficiency (bunch stem necrosis) High applications of K or ammonium can induce Mg deficiency symptoms even on soils that contain enough Mg.

Grapevines - Chlorosis

Symptoms
Magnesium deficiency causes interveinal yellowing (white vine) or reddening (red vine) on older leaves first. Discoloration starts on the leaf margin and proceeds towards the petiole attachment point. Leaf veins and an adjacent zone along them remain green, producing a characteristic palmate vein banding. At advanced stages, necrotic spots occur in the chlorotic areas and leaf margins turn necrotic brown.

Reasons
Magnesium deficiency Magnesium deficiency usually occurs in soils of low pH and where potassium is abundant. Symptoms can be easily confused with those of leaf roll virus.

Grapevines - Chlorosis

Symptoms
Magnesium deficiency causes interveinal yellowing (white vine) or reddening (red vine) on older leaves first. Discoloration starts on the leaf margin and proceeds towards the leaf base. Leaf veins and an adjacent zone along them remain green, producing a characteristic palmate vein banding.

Reasons
Magnesium deficiency Magnesium deficiency usually occurs in soils of low pH and where potassium is abundant.

Magnesium deficiency made worse by

Sandy soils
Acidic soils
Potassium rich soils
Soils receiving high potash applications
Cold wet periods

Magnesium is important for

Combats chlorosis giving healthier greener foliage
Increases alcohol content in berries
Increases sugar levels in berries
Prevents and controls grape stem necrosis

Yara recommended fertilizers for Magnesium

YaraTera KRISTA MgS

Grapevines: Apply 100-160 kg/ha in multiple applications from growth stage; early shoot growth to verasion. Refer to Yara crop program @ www.yara.com.au as a guide or contact your local Yara sales agronomist for advice.