Pre-harvest splitting (PHS) is one of those frustrating issues in citrus production that can sneak up on you and cost you dearly. In some seasons, it can lead to yield losses of up to 30% in susceptible cultivars. While it’s complex and often climate-driven, there are practical steps growers can take to reduce its impact.
Here’s what you need to know
What causes fruit splitting?
PHS happens when internal pressure from expanding pulp causes the rind to crack, usually at the styler end. The severity of splitting is often linked to:
- Climate stress, especially erratic weather during flowering and fruit set
- Heavy crop loads, leading to thinner rinds and more competition for resources
- Mineral imbalances, particularly potassium (K), phosphorus (P), and calcium (Ca)
- Water fluctuations, especially during stage II and III of fruit development
- Cultivar genetics, with some varieties naturally more prone to splitting
- Hormonal factors, especially in seedless cultivars
Split fruit doesn’t just drop prematurely, it also attracts pests and pathogens, which makes orchard hygiene even more critical.
What can be done?
There’s no silver bullet, but a combined management approach can make a real difference:
1. Pick the right cultivar
Some cultivars are more susceptible than others, especially thin-rinded mandarins and hybrids. Do your homework before planting: consult your cultivar management company and walk a few trial blocks to observe fruit behaviour.
2. Balance your nutrients
Keep K, P, and Ca within optimal ranges:
- K: 1.0–1.5%
- P: 0.1–0.16%
- Ca: 2.5–5.5%
Avoid over- or under-fertilising, as both can negatively impact rind structure.
3. Manage your irrigation carefully
- Avoid sharp fluctuations in soil moisture.
- Maintain good water availability in deeper soil layers (especially 40–80 cm).
- Steady, consistent watering supports rind elasticity and reduces splitting risk.
4. Use plant growth regulators (with caution)
- GA₃ (gibberellic acid) has been shown to strengthen rinds and delay rind ageing.
- 2,4-D (a synthetic auxin) may reduce splitting in some mandarin cultivars but should be applied with care due to potential quality impacts.
5. Watch your crop load
- Heavy crop years tend to show more splitting.
- Thinning fruit early (before physiological drop) can improve size and rind strength.
- Adjust irrigation and feeding in high-yield years to meet increased demand.
Final thoughts
PHS isn’t always avoidable, especially in seasons with extreme weather patterns, but with a holistic approach, its impact can be significantly reduced. Pay close attention to cultivar selection, nutrition, crop load, and water management. And when in doubt, lean on your local crop advisor for guidance.
For a deep dive into the research and technical background behind these recommendations, https://duroinursery.co.za/media/
