Apples - Chlorosis
Symptoms
Old leaves bluish-green with scorched margins (brown or grey). Margins may first appear light green and later turn necrotic. Necrosis progresses from the margins inward to the midrib.
Causes
Potassium deficiency
Frost and drought can cause similar symptoms
Apples - Necrosis
Symptoms
Old leaves bluish-green with scorched margins (brown or grey). Margins may first appear light green and later turn necrotic. Necrosis progresses from the margins inward to the midrib.
Causes
Potassium deficiency
Frost and drought can cause similar symptoms
Potassium deficiency made worse by
- Acidic soils (low pH)
- Sandy or light soils (leaching)
- Drought conditions
- High rainfall (leaching)
- or heavy irrigation
- Heavy clay (illite) soils
- Soils with low K reserves
- Magnesium rich soils
Potassium is important for
- New growth is healthy
- Cold hardiness is improved
- Flower number increases
- Fruit are longer and are generally more intensely coloured
- Fruit may mature earlier and have improved flavour
- Yields are increased
Yara recommended fertilisers for Potassium deficiency
YaraVita FOLIAR POTASH
Apple: 5 l/ha at bud burst. Also, two to three applications of 2 to 3 l/ha at 10 to 14 day intervals starting at petal fall. A further application of 5 l/ha may also be applied post-harvest before leaf fall. Water rate: 500 l/ha.
Read more about YaraVita FOLIAR POTASH
