> ## 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.
# Rubber Diagnosis: Decide What a Field Change Means and What to Do
> The starting point for interpreting rubber field changes across a 25 to 30 year cycle. Covers all three pillars: abiotic stress, nutrient disorders, and biotic stress, plus a scout-first decision tree keyed to leaf, panel, and root symptoms.
Rubber is a perennial tree crop on a 25 to 30 year cycle, tapped for 20+ years. Diagnosis happens at three scales: whole stand, cluster of trees, and individual tree with its tapping panel. Use this guide to move from a field observation or a satellite alert to a specific cause and a specific action.
For the standard census and inspection sequence a scout should follow on the ground, see [Field Walk Protocol](/guides/Crop/Rubber/field-walk-protocol).
## The three pillars
Drought, waterlogging, wind, lightning, cold. Weather and drainage driven, usually block-wide or gradient patterns.
N, P, K, Mg, Ca. Diagnosed by leaf color, stand vigor, and confirmed by leaf-tissue analysis on Whorl 2 leaves.
Root diseases, leaf diseases, panel diseases, insects, and TPD. Individual-tree and cluster-scale. Ground confirmation essential.
## Scout-first decision tree
Use what you see first to pick the pillar. The scout looks at four things on each tree, in this order.
### 1. Stand-level pattern
| What you see across the block | Likely pillar |
| ---------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Whole stand thinner than normal, uniform across the block | **Abiotic** (drought, over-tapping) or block-wide nutrient |
| Gradient across the block following topography or drainage | **Abiotic** (waterlogging) or soil-linked nutrient |
| Circular expanding patches of dying trees, often near old stumps | **Biotic** - [White root disease](/guides/Crop/Rubber/biotic/diseases/white-root) |
| Scattered dead trees along old rubber lines | **Biotic** - [Red root](/guides/Crop/Rubber/biotic/diseases/red-root) or [brown root](/guides/Crop/Rubber/biotic/diseases/brown-root) |
| Out-of-season leaf fall (not Feb-Apr wintering) | **Biotic** - [Corynespora leaf fall](/guides/Crop/Rubber/biotic/diseases/corynespora) or [Pestalotiopsis](/guides/Crop/Rubber/biotic/diseases/pestalotiopsis) |
| Delayed recovery after wintering | **Biotic** - [Powdery mildew](/guides/Crop/Rubber/biotic/diseases/powdery-mildew) |
| Slow whole-block NDVI decline over 1 to 3 years | **Biotic** - [Tapping Panel Dryness](/guides/Crop/Rubber/biotic/tpd) or chronic nutrient |
| Snapped or leaning trees after a storm | **Abiotic** - [Wind & lightning](/guides/Crop/Rubber/abiotic/wind) |
### 2. Leaf color and canopy (nutrient and leaf-disease decision)
Rubber leaf-tissue analysis uses **Whorl 2** leaves (the second whorl from the top, fully-expanded, sampled at 3 to 4 months old). This is the reference for nutrient sampling.
The table below moves from a **visible symptom** to a likely nutrient, one symptom at a time. It is a decision tree, not a verdict set. When a laboratory result comes back covering several nutrients at once a different rule applies: **name the most deficient and refuse the rest.** See [Reading a tissue analysis](/snippets/tissue-diagnosis).
| What you see | Where on the tree | Likely cause |
| ------------------------------------------------------------------ | ----------------- | ------------------------------------------------------------------------ |
| Whole canopy pale green | All leaves | [Nitrogen](/guides/Crop/Rubber/nutrient/nitrogen) |
| Older leaves yellow with red-purple margins | Lower whorl | [Magnesium](/guides/Crop/Rubber/nutrient/magnesium) |
| Older leaves yellow-orange with tip die-back | Lower whorl | [Potassium](/guides/Crop/Rubber/nutrient/potassium) |
| Small dark-green leaves, poor girth increment | All leaves | [Phosphorus](/guides/Crop/Rubber/nutrient/phosphorus) |
| Yellow young leaves, green veins | Upper canopy | [Calcium](/guides/Crop/Rubber/nutrient/calcium) or high pH |
| Brown or dark spots with yellow halo on leaves, out-of-season fall | Whole canopy | [Corynespora leaf fall](/guides/Crop/Rubber/biotic/diseases/corynespora) |
| Small tan spots with grey-white centers, needle-hole appearance | Whole canopy | [Pestalotiopsis](/guides/Crop/Rubber/biotic/diseases/pestalotiopsis) |
| White powdery growth on refoliating leaves | New growth | [Powdery mildew](/guides/Crop/Rubber/biotic/diseases/powdery-mildew) |
### 3. Trunk, panel, and roots (disease decision tree)
| What you see | Likely cause |
| --------------------------------------------------------------------- | -------------------------------------------------------------------- |
| White fan-shaped rhizomorphs on root collar, expanding cluster | [White root disease](/guides/Crop/Rubber/biotic/diseases/white-root) |
| Red-brown crust on roots, foul smell | [Red root](/guides/Crop/Rubber/biotic/diseases/red-root) |
| Dark brown crust encrusted with soil on roots | [Brown root](/guides/Crop/Rubber/biotic/diseases/brown-root) |
| Vertical black streaks running down the tapping panel from the cut | [Black stripe](/guides/Crop/Rubber/biotic/diseases/black-stripe) |
| Pink cottony growth on branch forks or trunk | [Pink disease](/guides/Crop/Rubber/biotic/diseases/pink-disease) |
| Tapping panel dries up, latex flow drops sharply on one or more trees | [Tapping Panel Dryness](/guides/Crop/Rubber/biotic/tpd) |
| Mud tubes on the trunk, hollow root collar | [Termites](/guides/Crop/Rubber/biotic/insects/termites) |
| Small brown or grey scales on young stems | [Bark scale](/guides/Crop/Rubber/biotic/insects/bark-scale) |
### 4. Latex flow and tapping cut (yield-critical decision tree)
| What you see | Likely cause |
| ------------------------------------------------- | ---------------------------------------------------------------- |
| Latex flow drops on a specific tree, cut goes dry | [Tapping Panel Dryness](/guides/Crop/Rubber/biotic/tpd) |
| Latex color grey or watery | Over-tapping, nutrient imbalance |
| Black vertical stripe on the panel below the cut | [Black stripe](/guides/Crop/Rubber/biotic/diseases/black-stripe) |
| Late-drip latex (dripping hours after tapping) | Bark damage from bad tapping cut |
| Reduced flow across the whole block | Drought, cold snap, or block-wide TPD |
| Green streak on new bark | Poor bark renewal, panel over-consumed |
### A latex yield comparison carries its panel and its tapping system
Every yield-drop trigger on rubber compares a block's latex output against its own recent baseline. That comparison is only valid if the tapping did not change underneath it.
**Tapping intensity sets yield directly.** A block moved from d/2 to d/3 produces less latex the following week, and a block opened on a new panel produces differently from one late in the previous panel. Neither change is visible from orbit — the canopy looks identical — so the satellite offers no correction and the drop reads as a stress signal.
A rubber yield comparison names its **panel** and its **tapping system**, or it is not a comparison. A block either side of a panel change, or either side of a change in tapping frequency, is two blocks as far as yield is concerned.
This applies to every `-15%` and `-25%` latex trigger in the rubber pages, including [Tapping Panel Dryness](/guides/Crop/Rubber/biotic/tpd) and [Potassium](/guides/Crop/Rubber/nutrient/potassium).
Tapping frequency and panel position are currently recorded as free-text scout notes rather than as fields, so **the platform cannot enforce this and does not claim to.** It shows the panel and the system alongside the comparison where a scout has recorded them, and leaves the judgement to the reader. Where nothing has been recorded, the comparison is shown with the gap named rather than suppressed — an unrecorded tapping change is a reason for doubt, not proof of one.
This is a **yield** rule. It does not govern index comparison, which is set by wintering and stand age — see [Rubber ecosystems](/guides/Crop/Rubber/rubber-ecosystems).
## Stand-age vulnerability
Different stresses matter at different ages. Use this alongside the pattern tables.
| Stand age | What matters most |
| ---------------------- | ------------------------------------------------------------------- |
| 0 to 1 year | Establishment failure, weed competition, termites, drought |
| 1 to 3 years | Cover-crop management, white root from old stumps, nutrient balance |
| 3 to 5 years | Canopy closure, powdery mildew after wintering, girth increment |
| 5 to 7 years (opening) | First tapping cut technique, black stripe risk, panel management |
| 7 to 20 years (prime) | CLF, Pestalotiopsis, TPD, over-tapping, root disease clusters |
| 20 to 25 years (late) | Root disease spread, wind lodging, replanting planning |
| Above 25 years | Senescence vs disease decisions; NDVI alone cannot separate them |
## How satellites contribute
Rubber's closed tall canopy makes it satellite-friendly but NDVI saturates. Match the tool to the question.
| Scale | Best for | Typical alert |
| --------------- | ------------------------------------------------------------ | --------------------------------------------------- |
| Block / canopy | Wintering, drought, out-of-season leaf fall, chronic decline | NDVI or NDRE anomaly vs same block year-over-year |
| Cluster | Root disease foci, wind damage, lightning strike zones | Localized NDVI drop expanding month to month |
| Individual tree | Panel dryness, single tree death | Not resolvable at Sentinel scale; use scout records |
The single biggest source of false alerts on rubber is the annual **wintering** dip in Feb to Apr. Judge the block against the [rubber ecosystems](/guides/Crop/Rubber/rubber-ecosystems) wintering stage table and the recovery test before dispatching a scout.
**Anomaly view is refused inside the wintering window** and cannot be used for this. Wintering shifts by clone, by state, and between Peninsular and East Malaysia, so a calendar-aligned year-over-year comparison across that boundary measures the shift in timing rather than the block. Outside the window, Anomaly is sound and is the right tool.
## Decision flow
Uniform, gradient, expanding cluster, or scattered? Use the block-level table above to pick the pillar before you walk in.
Follow the [Field Walk Protocol](/guides/Crop/Rubber/field-walk-protocol). Check leaf color and canopy, trunk and panel, roots at the collar, and latex flow.
Use the leaf, trunk/panel, and latex tables above to move from symptom to page.
Apply the recommended action, record the tree or block, and use the [Alerts](/guides/alerts-notifications) page to configure a follow-up.
## Related
* [Healthy NDVI ranges for rubber across planting environments](/guides/Crop/Rubber/rubber-ecosystems) - phase and wintering baselines.
* [Field Walk Protocol](/guides/Crop/Rubber/field-walk-protocol) - the standard scout inspection sequence.
* [Set up automated crop alerts](/guides/alerts-notifications) - configure the triggers that surface these stresses.
* [Analyze crop performance across a full season](/guides/seasonal-analysis) - the right tool for slow rubber decline.
This diagnosis covers the three major stress groups plus a scout-first decision tree. Rare stresses (herbicide phytotoxicity, hail, ozone, mineral toxicity) can be added as short reference pages later.