> ## 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 Nematodes in Pineapple

> Identify root-knot, reniform, and lesion nematodes in pineapple from slow diffuse decline, stunted twisted roots, and yield loss on replant blocks, and control with fallow, cover crops, resistant material, and nematicides.

Pineapple nematodes are a slow, quiet killer of yield. **Root-knot (Meloidogyne)**, **reniform (Rotylenchulus reniformis)**, and **lesion (Pratylenchus)** nematodes damage the root system, cause a slow diffuse block-wide decline, and are the main reason ratoon and replant blocks yield less than first-cycle blocks.

**Regional priority:** Very high on replant and ratoon blocks worldwide. Universal on sandy and BRIS soils.

## When pineapple is most vulnerable

From **establishment (month 0 to 3)** onward, worsening with each cycle. Damage is chronic and multiplicative if blocks are replanted without a fallow break.

## How nematodes show in satellite data

* **Slow, diffuse NDVI shortfall** over months - no clear pattern.
* **Block-wide** rather than patchy.
* **Same block flags cycle after cycle** if replanted without fallow.
* Very hard to distinguish from chronic nutrient deficiency without soil and root sampling.

## Field symptoms

* **Stunted plants** with short D-leaves
* **Slow, diffuse block-wide decline** over months
* **Roots stunted, thick, and twisted** with knots (root-knot) or short and dark (lesion, reniform)
* **Few feeder roots** for the plant's age
* **Reduced fruit size** and yield
* **Poor response to fertilizer** despite adequate soil test values
* **Overlap with waterlogging** - separate by drainage pattern; nematodes are block-wide, waterlogging is zone-specific

## Reduce the damage by

* **Soil and root sampling before replanting** - nematode counts guide the fallow decision.
* **Fallow with grass** (Brachiaria, Panicum) or legume for 6 to 12 months between cycles.
* **Cover crops** with nematicidal roots (marigold, mucuna, sunn hemp) plow-under.
* **Hot water treatment of suckers** (50 C, 30 min) kills nematodes in planting material.
* **Nematicide at planting** on chronic blocks - fenamiphos, oxamyl, or fluopyram where approved.
* **Do not replant immediately** after a heavily infected block - the yield loss will compound.
* **Rotate to non-host crops** where possible (grass, cereals) rather than back-to-back pineapple.

## Set an alert for early warning

<Tip>
  Turn the diagnosis into a trigger. Nematode damage is chronic and cycle-scale, so use anomaly alerts and scheduled soil sampling.
</Tip>

Recommended settings for nematodes on pineapple:

* **Anomaly alert** - trigger on persistent (> 90 days) block-wide NDVI shortfall of 5% or more below the phase baseline.
* **Pre-replant soil sampling reminder** - schedule nematode counts 3 months before any planned replant.
* **Fallow-tracking flag** - mark blocks that were replanted with less than 6 months fallow for close monitoring.

## Related

* [Pineapple Diagnosis](/guides/Crop/Pineapple/pineapple-diagnosis)
* [Symphylids](/guides/Crop/Pineapple/biotic/insects/symphylids) - similar root-damage pattern; separate by direct root inspection.
* [Set up automated crop alerts](/guides/alerts-notifications)