> ## 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 Heart Rot (Phytophthora) in Pineapple

> Identify Phytophthora heart rot in pineapple from center-whorl collapse with foul smell in wet spots, and control with drainage, resistant planting material, and metalaxyl or fosetyl-Al drenches.

Heart rot, caused by **Phytophthora nicotianae** (and P. cinnamomi as root rot), is the single fastest killer on pineapple. Cool, wet weather and poor drainage let the pathogen enter the leaf axil, rot the growing point, and kill the plant within days. Outbreaks cluster in wet spots and can wipe out low-lying zones after a single heavy rain.

**Regional priority:** Very high across all wet-season and peat blocks. High on flat or poorly drained mineral upland after cyclonic rain.

## When pineapple is most vulnerable

All phases, but the highest mortality is at **early vegetative (young plants) and late vegetative to fruit development** when whole mature plants collapse. Cold, wet weather (below 25 C, high rainfall) is the classic outbreak trigger.

## How heart rot shows in satellite data

* **Sudden localized NDVI drop** in wet spots 5 to 14 days after a heavy rain event.
* **Circular or irregular patches** that can expand between passes.
* **Cluster pattern in low-lying zones** matches drainage maps.
* Best early signal: NDWI spike (wet zone) followed by NDVI drop.

<Warning>
  Any pineapple block with a rainfall event greater than 50 mm in 24 hours should be scouted within 48 hours, even before satellite confirmation. Heart rot mortality happens fast.
</Warning>

## Field symptoms

* **Center whorl leaves pull out with a foul, fishy smell** - the diagnostic test
* **Yellowing and tilting** of the center rosette 5 to 10 days after infection
* **Plant collapse** with soft, rotten base
* **Wet-spot cluster** of dead and dying plants after rain
* **White fungal mycelium** at the base of the whorl in humid weather
* Older plants and stressed plants (waterlogging, mealybug wilt) affected first

## Reduce the damage by

* **Improve drainage** - the single most effective control. Lateral drains every 30 to 50 m, raised beds, cleared canals.
* **Use disease-free planting material** - dip suckers and slips in fosetyl-Al or metalaxyl before planting.
* **Preventive drench** on high-risk blocks before the wet season - metalaxyl or fosetyl-Al soil drench.
* **Foliar phosphonate (potassium phosphite)** on high-risk blocks - systemic, effective, low-toxicity.
* **Destroy infected plants** immediately - pull, bag, and remove from the block. Do not compost on-site.
* **Rotate to grass or non-host crops** on blocks with chronic history before replanting.
* **Avoid mechanical wounding** in wet weather; wounds are entry points.
* **Boot and tool hygiene** - wash between blocks to avoid spreading zoospores.

## Set an alert for early warning

<Tip>
  Turn the diagnosis into a trigger. Heart rot is fast; combine a rainfall alert with an NDVI/NDWI follow-up so a scout is dispatched within 48 hours.
</Tip>

Recommended settings for heart rot on pineapple:

* **Weather alert** - rainfall greater than 50 mm in 24 hours triggers a dispatch to all blocks in the receiving area.
* **NDWI + NDVI follow-up** - trigger a specific-block alert on a zone with NDWI spike (+0.10) followed within 2 weeks by NDVI drop (0.08 or greater).
* **Cluster growth alert** - trigger when a flagged zone expands between two consecutive satellite passes.

## Related

* [Pineapple Diagnosis](/guides/Crop/Pineapple/pineapple-diagnosis)
* [Waterlogging](/guides/Crop/Pineapple/abiotic/waterlogging) - the top predisposing factor.
* [Root rot](/guides/Crop/Pineapple/biotic/diseases/root-rot) - same pathogen genus, different symptom pattern.
* [Set up automated crop alerts](/guides/alerts-notifications)