> ## Documentation Index
> Fetch the complete documentation index at: https://badixth-dc85e378.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Diagnose and Respond to Root Rot (Phytophthora cinnamomi) in Pineapple

> Identify Phytophthora cinnamomi root rot in pineapple from tipped-over plants with black rotted bases in chronic wet zones, and control with drainage, raised beds, and phosphonate treatment.

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.

## 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.

## 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).

## 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)

## 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.

## Set an alert for early warning

<Tip>
  Turn the diagnosis into a trigger. Root rot is chronic and zone-specific, so use the anomaly view rather than event alerts.
</Tip>

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.

## Related

* [Pineapple Diagnosis](/guides/Crop/Pineapple/pineapple-diagnosis)
* [Waterlogging](/guides/Crop/Pineapple/abiotic/waterlogging) - the predisposing factor.
* [Heart rot](/guides/Crop/Pineapple/biotic/diseases/heart-rot) - fast-acting sibling.
* [Fusariosis](/guides/Crop/Pineapple/biotic/diseases/fusariosis) - overlapping basal rot; separate by pattern.
* [Set up automated crop alerts](/guides/alerts-notifications)