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Root rot, caused mainly by Phytophthora cinnamomi, is the slower, chronic sibling of heart rot. Instead of collapsing the growing point after a wet event, it rots the root system and lower stem over weeks, causing plants to tip over. It is a long-term drainage problem, not a single-event problem. Regional priority: High on flat, poorly drained blocks; peat blocks with poor canal maintenance; and any block with a history of heart rot.

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When pineapple is most vulnerable

All phases, but visible losses peak at late vegetative and fruit development when the fruit weight tips over the compromised root plate.

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How root rot shows in satellite data

  • Chronic NDVI shortfall in low-lying zones - the same zones flag cycle after cycle.
  • Anomaly view shows a persistent lower-than-block-average zone.
  • Less sudden than heart rot; slower onset, longer decline.
  • Confirm on the ground with heart pull (firm) plus root inspection (black, mushy).

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Field symptoms

  • Tipped-over fruiting plants with root plate lifted
  • Black, mushy, few feeder roots when the plant is uprooted
  • Basal stem soft and dark but heart may still be intact (distinguishes from heart rot)
  • Chronic gap zones in the same low-lying areas across cycles
  • Poor sucker production on affected plants
  • Overlap with fusariosis - separate by pattern (root rot follows drainage; fusariosis follows wounds and headlands)

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Reduce the damage by

  • Fix drainage permanently - this is a chronic drainage problem, not a spray problem. Lateral drains, raised beds, cleared canals.
  • Replant chronic zones on raised profile beds at least 30 cm above the furrow.
  • Foliar phosphonate every 2 to 3 months on high-risk blocks - systemic, protects roots.
  • Metalaxyl or fosetyl-Al soil drench at planting on known infected blocks.
  • Use disease-free planting material - dip suckers before planting.
  • Break the cycle with a grass or legume rotation on chronic blocks before replanting.
  • Avoid compaction - compacted layers hold water at the root zone.

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Set an alert for early warning

Turn the diagnosis into a trigger. Root rot is chronic and zone-specific, so use the anomaly view rather than event alerts.
Recommended settings for root rot on pineapple:
  • Anomaly alert - trigger on persistent (> 60 days) NDVI anomaly in a specific zone across cycles.
  • Drainage inspection reminder - schedule an annual canal and lateral-drain check on all blocks with a root-rot history.
  • Planting-material check - flag any planting round on affected blocks that skips the pre-plant dip.