phytophthora root rot on Citrus
Quick answer
If your Citrus has phytophthora root rot, the most likely cause is: Phytophthora parasitica and P. citrophthora cause citrus root rot by colonizing fibrous roots under waterlogged conditions, with sour orange (Citrus aurantium) showing 100% mortality versus Volkamer lemon (C. volkameriana) at 33% in infected soils.
Start here:
- 1. Test rootstock susceptibility before planting: avoid sour orange in Phytophthora-infested soils
- 2. Apply combined fungicide treatment (pre-planting foliar spray + soil drench) using Ridomil at 5g/L or Aliette at 5g/L for complete 100% disease control
Why Citrus gets phytophthora root rot
Phytophthora parasitica and P. citrophthora cause citrus root rot by colonizing fibrous roots under waterlogged conditions, with sour orange (Citrus aurantium) showing 100% mortality versus Volkamer lemon (C. volkameriana) at 33% in infected soils.
How to reverse phytophthora root rot on Citrus
- 1
Test rootstock susceptibility before planting: avoid sour orange in Phytophthora-infested soils
- 2
Apply combined fungicide treatment (pre-planting foliar spray + soil drench) using Ridomil at 5g/L or Aliette at 5g/L for complete 100% disease control
- 3
Ensure proper soil drainage and avoid over-irrigation to prevent anaerobic conditions that favor pathogen proliferation
- 4
Monitor roots for discoloration at 60-day intervals after treatment
Keep phytophthora root rot off this Citrus
Plant resistant rootstocks (Volkamer lemon, Swingle citrumelo, trifoliate orange) in well-drained soils and apply Ridomil or Aliette as combined foliar+drench treatment at planting.