When to run this protocol
- Monthly during immature phase (year 1 to 5) and during prime tapping
- Every 2 weeks during wintering to refoliation (Feb to Apr in Peninsular Malaysia)
- Immediately on any block flagged by a satellite alert or when neighboring blocks report an outbreak
- Within 48 hours of a storm event (wind, lightning, heavy rain)
- Quarterly root-disease sweep near old stumps and along block boundaries
- At each tapping round for tappers, focused on panel condition
What to bring
- Block map with tree lines and the planned walk transect
- Tree-level record sheet or mobile app tied to the field data model
- Sharp knife (bark and cut inspection)
- Trowel or hand pick (root inspection at collar)
- Hand lens (10x) for scale, mites, spore inspection
- Girth tape (30 cm and 150 cm marks)
- Latex flow sample cup for TPD suspects
- Sample bags for Whorl 2 leaf, bark, and root samples
- Camera or phone (photograph every anomaly)
- GPS for stop-level and single-tree records
- Boots and mud gaiters (rubber blocks are usually wet)
Choose a walk pattern
Inspect the block along a fixed pattern so results are repeatable year over year.
At each stop, inspect 10 consecutive trees along one line. Always keep the same stop count on the same block so trends compare cleanly.
The 5-step inspection sequence
Run each step at every stop, in this order. Skipping a step is the most common cause of missed diagnoses.1
Stand from row-end
Look down the tree line from the row-end first. This tells you about canopy uniformity and gaps before you get close.
- Canopy uniformity - even fullness and color, or patchy? (Wintering, CLF, Pestalotiopsis, chronic nutrient)
- Dead or dying trees - grouped or scattered? (Root disease cluster vs scattered wind/lightning/TPD)
- Circular expanding patches - white/red/brown root disease focus
- Leaf litter under trees - out-of-season leaf drop is a strong CLF or Pestalotiopsis signal
- Gap count - how many missing or dead trees in the 10-tree sample? (Baseline for later comparison)
- Weed pressure - immature blocks with poor cover crop, or mature blocks with weedy inter-row?
- Standing water - present after 24 hours in furrows or low ground? (Drainage risk, root rot risk)
- Cover crop condition - immature blocks only; declining legumes flag nutrient or shade issues
2
Leaf color, canopy, and Whorl 2 (nutrient and leaf-disease decision)
Look up into the canopy of 5 representative trees. Whorl 2 leaves (second whorl from the top, fully expanded, 3 to 4 months old) are the reference for nutrient assessment and tissue sampling.
- Whole canopy pale green - Nitrogen
- Older leaves yellow, red-purple margins - Magnesium
- Older leaves yellow-orange, tip die-back - Potassium
- Small dark leaves, slow girth - Phosphorus
- Young leaves yellow, green veins - Calcium
- Brown-black lesions with yellow halo, out-of-season fall - Corynespora leaf fall
- Tan spots with grey-white centers - Pestalotiopsis
- White powder on refoliating leaves - Powdery mildew
3
Trunk, tapping panel, and pink disease check
Walk to every tree in the 10-tree sample. Inspect the tapping panel (if tapped) and the trunk from ground to branch fork.
- Vertical black streaks below the tapping cut - Black stripe (Phytophthora)
- Latex flow reduced or absent from part of the cut - early Tapping Panel Dryness
- Whole panel dry, latex flow zero - advanced TPD
- Pink cottony growth at branch fork or trunk - Pink disease
- Bark wounds, poor bark renewal, green-streak new bark - bad tapping technique, panel over-consumed
- Mud tubes on the trunk - Termites
- Small brown or grey scales on young stems - Bark scale
- Bark canker or open wound - stem canker, treat and record
- Latex color - normal white; grey or watery indicates over-tapping or TPD onset
4
Root collar and stump base (only every quarter and on all root-disease suspects)
Scrape the topsoil at the base of every 3rd tree in the sample, and around any dying or dead tree.
- White fan-shaped rhizomorphs on the collar, spreading over roots - White root (Rigidoporus microporus)
- Red-brown crust on the roots, foul smell - Red root (Ganoderma philippii)
- Dark brown crust with soil encrusted - Brown root (Phellinus noxius)
- Hollowed collar, mud galleries - Termites
- Old stump within 5 m - flag as a root-disease reservoir
- Adjacent dead tree in a line or cluster - expanding focus; check every neighboring tree
5
Latex flow, panel management, and yield (only on tapped blocks)
On tapping days, cross-check the tapper’s record for the 10-tree sample.
- Flow drop on individual trees - flag for TPD, black stripe, or bark damage
- Whole-block flow drop - drought, cold snap, or block-wide TPD
- Late-drip latex (still dripping hours after tapping) - poor cut, over-tapping
- Panel utilization - how much virgin bark left on the tree? (Replanting decision input)
- Cut depth and slope - visual inspection; poor cuts cause bark damage that opens black stripe and pink disease
- DRC (dry rubber content) trend - block-wide drop can signal over-stimulation or nutrient imbalance
What to record per stop
Minimum record at every stop, whether the block is normal or not:Block-level summary to record
After walking a block, record:- Number of stops inspected and total trees inspected
- Total gap count across all stops and estimated block-level stand percentage
- Number and location of root-disease trees (destroyed / treated / pending)
- Number of TPD trees (rested / tapped / abandoned)
- Pattern (scattered, edge, expanding focus, out-of-season leaf fall, whole-block)
- Recent weather, wintering stage, and tapping frequency
- Recommendation (treat, resample, rest panel, escalate, or continue monitoring)
Pattern reading (what it likely means)
Use the walk-wide pattern to decide which pillar to open in the Rubber Diagnosis guide.Linking to satellite alerts
If you were sent to this block by a satellite alert:- Confirm the alerted zone on the ground. Walk into it and take at least 3 in-zone stops + 2 control stops outside the zone.
- Record whether the pattern matches (whole-block, gradient, expanding cluster, or line).
- Cross-check the index that moved (NDVI, NDRE, NDWI) against the Rubber Diagnosis decision flow. Remember to check the wintering window and NDVI saturation for mature stands.
- Use the Rubber Diagnosis tables to move from the field pattern to a specific cause.
- Set a follow-up alert on the same block or zone via the Alerts page.
Safety and hygiene
- Wash tools and boots between blocks. Root pathogens (white root, red root, brown root) survive in soil and wood chips.
- Never move stump wood or old-rubber logs from an infected block to a clean one.
- Avoid scouting during heavy rain or lightning. Rubber blocks are the tallest structure in many landscapes.
- Wear long sleeves and repellent. Snake and mosquito exposure is real, especially in mature stands and lowland blocks.
- If tapping is in progress, do not walk under an actively tapped tree; latex drips and cups are set below the cut.
- Report any hazardous conditions (fallen trees, snake sightings, boundary disputes) immediately.
Related
- Rubber Diagnosis - the decision tree that this walk feeds into.
- Healthy NDVI ranges for rubber across planting environments - the baseline your inspection compares against.
- Set up automated crop alerts - the triggers that dispatch this walk.
- Plan and execute field scouting routes - the mobile-app workflow that captures the records above.