Skip to main content
Boron is required for cell division and pollen viability. On pineapple, deficiency shows as cracked and corky young leaves and cracked, misshapen fruit with internal cavities. B is easily leached from sandy soils and locked up at high pH. Regional priority: Moderate on sandy, BRIS, and calcareous soils. Under-diagnosed in many operations because symptoms overlap with Ca and fruit borer damage.

​
When pineapple is most vulnerable

At forcing (month 12 to 14) and again at fruit set (month 14 to 16) - the two windows where cell division is most active in the developing inflorescence and fruit.

​
How boron deficiency shows in satellite data

  • Not detectable at Sentinel scale.
  • Confirm by D-leaf analysis and fruit inspection at harvest.

​
Field symptoms

  • Young leaves cracked, corky, or brittle - snap when bent
  • Fruit with corky patches and skin cracks
  • Internal cavities and misshapen “knobby” fruit
  • Poor sucker and slip production in chronic deficiency
  • Overlap with Ca deficiency on fruit - both cause cracking. B affects both young leaves and fruit; Ca mainly affects fruit and older-leaf edges.

​
Reduce the damage by

  • Foliar borax or Solubor (0.2%) applied to the leaf axil at forcing and again at fruit set.
  • Broadcast borax at planting on known deficient blocks - 5 to 15 kg/ha, incorporated. Do not exceed 20 kg/ha; B toxicity is a real risk.
  • Do not tank-mix B with foliar Ca at high concentrations - they can precipitate. Apply separately.
  • Keep soil pH below 6.5 to keep B available.
  • D-leaf analysis - target 20 to 40 ppm B in the D-leaf. This is a generic target with no site, soil, cultivar or season qualifier, so it supports inside or outside and no finer grade — see Reading a tissue analysis.
Boron has a narrow window between deficiency and toxicity. Follow label rates strictly. B toxicity shows as leaf tip and margin burn similar to salinity.

​
Set an alert for early warning

Turn the diagnosis into a trigger. B deficiency shows at forcing and fruit set, so build the alert around scheduled foliar reminders.
Recommended settings for boron on pineapple:
  • Foliar B reminder - schedule sprays at forcing (month 12 to 13) and fruit set (month 14 to 15) on all blocks; skip only where D-leaf B is above 30 ppm.
  • D-leaf sampling reminder - month 10, before forcing.
  • Fruit-quality tracking - flag blocks with cull rate above 8% for cracked or knobby fruit.