> ## 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 Rice Stem Borers

> Identify stem borers (yellow, striped, pink, dark-headed) from deadhearts in vegetative stage and whiteheads at heading, and control them with resistant varieties, egg-mass destruction, and biological control.

Stem borer larvae tunnel inside the rice stem, cutting off water and nutrient supply to the tiller. At vegetative stage, this kills the central growing point and produces a **deadheart** (dead central tiller pulled out easily). At reproductive stage, it cuts the panicle base and produces a **whitehead** (pale, empty panicle standing above the crop).

The main species are yellow stem borer (*Scirpophaga incertulas*), striped stem borer (*Chilo suppressalis*), pink stem borer (*Sesamia inferens*), and dark-headed stem borer (*Chilo polychrysus*). Management is similar across species.

## When rice is most vulnerable

Entire vegetative to reproductive period. Vegetative-stage damage causes deadhearts; reproductive-stage damage causes whiteheads. Whiteheads cause greater yield loss because the tiller is no longer replaceable.

## How stem borers show in satellite data

* **Whiteheads at heading** appear as small pale flecks and, in heavy infestations, as reduced field-scale NDVI at the reproductive stage.
* Deadhearts at tillering do not usually cross the detection threshold from satellite - the plant compensates with new tillers.
* Sudden pale patches after heading, with no weather cause, are a stem-borer signal.

<Warning>
  Whiteheads look the same from above whether caused by stem borer, neck blast, drought at flowering, or sheath rot. Ground confirmation is essential.
</Warning>

## Field symptoms

* **Deadheart** (vegetative stage): central tiller dries out and can be pulled out easily; the rest of the plant looks normal
* **Whitehead** (reproductive stage): whole panicle is pale, dry, empty, and stands above the healthy crop
* Larval tunnels visible when the stem is split open
* Frass (insect droppings) in the tunnels
* Egg masses on leaves - flat cream/brown patches near the leaf tip

## Reduce the damage by

* **Grow moderately resistant varieties** where available.
* **Destroy egg masses** during weeding and hand-remove infested tillers.
* **Synchronized planting** and destruction of stubble between seasons reduces the carryover population.
* **Preserve natural enemies** - egg parasitoids (Trichogramma) provide substantial free control. Avoid broad-spectrum insecticides.
* **Release Trichogramma cards** where they are available and locally validated.
* **Selective insecticide** (chlorantraniliprole or cartap) only if scouting shows the economic threshold is crossed. Apply based on egg-mass counts, not calendar.
* **Do not spray at heading** to protect pollinators and beneficials.

## Set an alert for early warning

<Tip>
  Turn the diagnosis into a trigger. Focus alerts on the reproductive stage where whiteheads become detectable.
</Tip>

Recommended settings for stem borers on rice:

* **NDVI drop alert** during heading - trigger on a drop of 0.08 or more.
* **New Imagery alert** during the two weeks around heading so early whitehead patches are caught quickly.

## Related

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