> ## 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 Sheath Rot in Rice

> Identify sheath rot from discolored flag-leaf sheaths and unemerged or partly emerged panicles, and control it with balanced N, wider spacing, and clean seed.

Sheath rot, caused primarily by *Sarocladium oryzae*, attacks the flag leaf sheath. Because the panicle emerges through the flag leaf sheath, sheath rot often traps or damages the panicle at heading. It thrives in dense high-N canopies with insect wounds, especially after brown planthopper or stem borer damage.

## When rice is most vulnerable

Booting through heading. Wounding by insects, high plant density, and continuous flooding all raise risk.

## How sheath rot shows in satellite data

* **Fields with heading failure** show lower-than-expected NDVI at heading and no proper reproductive-stage green-up.
* Poor separation from neck blast at the satellite level - use ground scouting and stubble examination.

<Warning>
  A field that never green-fills at heading is a strong signal. Cause could be sheath rot, neck blast, drought at flowering, or panicle stem borer. Scout to separate them.
</Warning>

## Field symptoms

* Oblong to irregular brown lesions on the flag leaf sheath, often with a pale center
* Panicle fails to emerge fully, or emerges twisted and discolored
* Powdery whitish growth inside the affected sheath in humid conditions
* Unfilled or discolored grains; empty spikelets

## Reduce the damage by

* **Use clean, treated seed** - sheath rot is seed-transmitted.
* **Avoid excessive N** and dense planting.
* **Manage stem borer and brown planthopper** - insect wounds are a major entry point.
* **Grow moderately resistant cultivars** where available.
* **Balance nutrients** - adequate K and Si reduce severity.
* **Fungicide** may be justified at booting on chronic sheath-rot fields; use only with scouting evidence.

## Set an alert for early warning

<Tip>
  Turn the diagnosis into a trigger. Sheath rot is best caught by comparing expected vs actual reproductive-stage NDVI, so schedule reviews at heading.
</Tip>

Recommended settings for sheath rot on rice:

* **NDVI threshold alert** at heading - trigger when NDVI is below your ecosystem baseline for the reproductive stage.
* **New Imagery alert** during heading so failed heading is caught within days.

## Related

* [Rice Diagnosis](/guides/Crop/Rice/rice-abiotic-stress)
* [Set up automated crop alerts](/guides/alerts-notifications)