Leaves develop inteveinal necrosis or necrotic blotches from midrib area on older leaves first
Magnesium deficiency
Potassium deficiency perhaps produces similar symptoms, but starts at leaf margins.
Symptoms appear first as chlorosis between the main veins, starting on older leaves. Then develop to interveinal necrosis or necrotic blotches along the main vein. Often leaf margin remain green.
Apple and other fruits sometimes right away develop necrosis without preceding chlorosis.
Magnesium deficiency
Potassium deficiency perhaps produces similar symptoms, but starts on the leaf margins.
Symptoms appear first as chlorosis between the main veins starting on older leaves. Then develop to interveinal necrosis or necrotic blotches along the main vein. Often leaf margin remain green.
Apple and other fruits somtimes right away evolve necrosis without preceding chlorosis.
Magnesium deficiency
Potassium deficiency perhaps produces similar symptoms, but starts at leaf margins.
Symptoms appear first as chlorosis between the main veins starting on older leaves. They develop to interveinal necrosis or necrotic blotches along the main vein. Often leaf margins remain green.
Apple and other fruits sometimes evolve necrosis without preceding chlorosis.
Magnesium deficiency
Potassium deficiency perhaps produces similar symptoms, but starts at leaf margins.