Symptoms
Intercostal yellowing on entire leaflets usually starting on younger leaves. Necrosis at leaf edge may be due to severe deficiency but it occurs usually in spots along the line of the veins.
Reasons
Manganese deficiency
Nightfrosts can cause similar symptoms. Magnesium deficiency is similar but here yellowing usually starts on older leaves.
Manganese deficiency is normally limited to high pH soils, where manganese in the soil is unavailable for the plants. Manganese deficiency occurs on medium to low pH soils, if the soil preparation has created a loose soil with high oxygen content.
Symptoms
Symptoms start on younger leaves. Leaf veins first remain green, but black spots develop along the line of the veins. Leaves near shoot tip small and chlorotic/necrotic.
Reasons
Severe manganese deficiency.
Could be confused with late blight (Phytophthera infestans) but manganese deficiency has no smell and necrosis of stem base.
Manganese deficiency is normally limited to high pH soils, where manganese in the soil is unavailable for the plants. Manganese deficiency occurs on medium to low pH soils, if the soil preparation has created a loose soil with high oxygen content.
Symptoms
Symptoms start on younger leaves. Leaves turn pale green/yellow followed by black spots developing along the line of the veins.
Reasons
Manganese deficiency.
Manganese deficiency is normally limited to high pH soils, where manganese in the soil is unavailable for the plants. Manganese deficiency occurs on medium to low pH soils, if the soil preparation has created a loose soil with high oxygen content.
Symptoms
Symptoms start on younger leaves. Leaf veins first remain green, but black spots develop along the line of the veins. Slight cupping of entire leaflets. Leaves near shoot tip small and chlorotic/necrotic.
Reasons
Severe manganese deficiency (back side of leaf)
Could be confused with late blight (Phytophthera infestans) but manganese deficiency has no smell and necrosis of stem base.
Manganese deficiency is normally limited to high pH soils, where manganese in the soil is unavailable for the plants. Manganese deficiency occurs on medium to low pH soils if the soil preparation has created a loose soil with high oxygen content.
Symptoms
Symptoms start on younger leaves. Leaf veins first remain green, but black spots develop along the line of the veins. Slight cupping of entire leaflets. Leaves near shoot tip small and chlorotic/necrotic.
Reasons
Severe manganese deficiency (back side of leaf)
Could be confused with late blight (Phytophthera infestans) but manganese deficiency has no smell and necrosis of stem base.
Manganese deficiency is normally limited to high pH soils, where manganese in the soil is unavailable for the plants. Manganese deficiency occurs on medium to low pH soils if the soil preparation has created a loose soil with high oxygen content.
Potatoes: 1 l/ha 1 week after 100% emergence. For moderate to severe deficiency, repeat applications may be necessary at 10-14 day intervals. A further application may be made following petiole analysis, during tuber bulking. Water rate: 200 l/ha.
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