Golden pruning tips for pistachio trees
- Timing: Late winter, before bud swell, on dry days. In cold regions, wait until the main frost risk has passed. Avoid heavy pruning in autumn.
- Ideal form: Open vase or modified leader with 4–5 strong primary scaffolds set at 50–70° angles and 15–25 cm of vertical spacing.
- Trunk height: About 100–120 cm for airflow and compatibility with mechanized harvest.
- Cut type: Prefer thinning cuts over heading cuts so light penetrates the canopy and fewer watersprouts are produced.
- Shoot selection: Remove upright shoots inside the canopy, crossing/rubbing limbs, and dead, diseased, or broken wood; keep outward, wide-angled branches.
- Managing alternate bearing: In on-years, prune a bit harder (to stimulate vegetative growth and moderate next year’s crop); in off-years, prune more lightly.
- Males vs. females: Prune male trees slightly harder with light heading to produce more one-year-old wood (spring pollen source); prune female trees more
gently to preserve fruiting wood.
- Cut hygiene: Prune only in dry weather; disinfect tools with 70% alcohol or sodium hypochlorite; remove and destroy diseased debris
(risk of Botryosphaeria/Cytospora canker).
- Sunscald protection: After opening the canopy and making large cuts, whitewash interior branches with diluted white latex paint (1:1 with water).
- After pruning: Dial back irrigation and nitrogen slightly to control watersprout growth; avoid leaving “stubs”—cut just outside the branch collar.
Training from sapling to bearing (first 3 years)
- Year 1:
- Head the sapling at 100–120 cm and tie it to a stake.
- Summer: keep 3–5 shoots with good angles and directions; pinch/remove the rest gently. Use spreaders/clips to widen branch angles if needed.
- Year 2 (winter):
- Finalize 4–5 primary scaffolds spaced around the trunk with adequate vertical spacing; remove the rest.
- Lightly head each scaffold (about 1/4–1/3) to an outward bud to promote good secondary branching; head stronger scaffolds less and weaker ones a bit more to
balance vigor.
- Year 3:
- On each scaffold, choose 2–3 secondary branches with proper spacing and direction; remove upright shoots inside the canopy and competing limbs.
- Keep the center open for light and air.
Maintenance pruning of bearing trees
- Remove about 10–15% of wood each year, smartly placed. Focus on thinning shaded and crossing branches rather than heavy heading.
- Pistachio bears on one-year-old wood; ensure ample light reaches this wood and avoid unnecessary heading that creates watersprouts.
- Summer green pruning: snap off basal suckers and vertical watersprouts while they’re soft to leave small wounds.
- Professional cuts: Don’t cut into the branch collar, and don’t leave stubs. Use the three-cut method on thick limbs to prevent bark tearing.
- Fruit sanitation: Remove mummified clusters and infected shoots to reduce disease inoculum.
Common mistakes (and quick fixes)
- Pruning too early in mid-winter cold → wait until major frost risk has passed.
- Heavy heading on mature trees → use thinning and targeted light management instead.
- Leaving tight angles in early years → use clips/spreaders to set wide angles.
- Skipping whitewash after opening the canopy → whitewash interior to prevent sunscald and canker.
- Not disinfecting tools in diseased orchards → disinfect between trees, especially in infected blocks.
Quick calendar
- Winter (main): Structural shaping/thinning on dry days, after frost risk and before bud swell.
- Spring: Review cuts, remove wind/frost damage; minimal pruning.
- Summer: Light green pruning (suckers and watersprouts), maintain internal light.
- Autumn: Postharvest sanitation only; avoid heavy pruning.
Best pruning window in dry vs. humid regions
- Dry (semi-arid to arid)
- Ideal: Late winter, after severe frost risk and before bud swell.
- Typical window (Northern Hemisphere/Iran): roughly Feb 4–Mar 15 (15 Bahman to 25 Esfand), ±10 days depending on year and cultivar.
- Key: If a cold snap returns, pause for a few days until it passes, then continue.
- Humid (frequent rain/fog)
- Ideal: Also late winter, but only during a 2–5 day dry spell; cuts should dry quickly to reduce canker/rot risks.
- Typical window: about Mar 1–15 (10–25 Esfand), contingent on a rain-free forecast. If rains persist and buds are near swelling, postpone heavy pruning and do
only minimal sanitation; plan light summer green pruning instead.
Why this window?
- In late dormancy, reserves are high and frost risk is lower; wounds callus faster and fewer watersprouts are induced. In humid climates, post-cut dryness is the
single most important factor to reduce disease.
Quick decision checklist
- Buds are still firm with scales closed (not swollen/green).
- Night minima above ~0 to −2°C for several consecutive days (major frost past).
- 48–72 hours forecast without rain/heavy fog; midday relative humidity lower.
- Tools disinfected; cuts made on dry days; whitewash interior branches exposed to sun.
Additional notes
- Male trees can be pruned slightly earlier and a bit harder than females, but the overall window is similar.
- Avoid heavy autumn pruning, and avoid late pruning after bud swell except to remove broken/diseased wood.
Open vase training steps for 1- to 5-year-old trees
Goals of the open vase
- Straight trunk to 100–120 cm (for ventilation and harvest).
- 4–5 strong primary scaffolds at 50–70°, evenly spaced around the trunk with 15–25 cm vertical separation.
- Keep the center open for light and air.
- Light, purposeful heading; favor thinning over heavy cuts.
- Timing: late winter (after frost, before bud swell) + light summer green pruning.
Year 1 (planting to year-end)
- Winter/at planting:
1) Head the tree at 100–120 cm and stake firmly.
2) Keep the trunk clean up to ~70–80 cm; you may leave a few small temporary leafy shoots to thicken the trunk (remove next winter).
- Summer:
1) Select 3–5 shoots with wide angles in different directions; remove competing soft shoots/buds.
2) Open angles to 50–70° with clips/spreaders.
3) Remove very upright interior shoots and crossing ones. Avoid heavy summer heading (promotes watersprouts).
Year 2
- Winter:
1) Finalize 4–5 scaffolds; remove central/competing leaders to keep the center open.
2) Lightly head each scaffold (about 20–30%) to an outward bud to build secondaries.
3) Balance vigor: on very strong scaffolds, use reduction/redirect cuts to a weaker lateral; on weak ones, very light heading or just thinning.
4) Remove inward, tight-angled, and rubbing branches. If the canopy opens, whitewash interior surfaces exposed to sun.
- Summer:
1) Break/remove soft watersprouts/upright shoots inside the canopy.
2) Maintain angles; tie or lightly weight if needed.
Year 3
- Winter:
1) On each scaffold, select 2–3 secondaries spaced 25–40 cm apart in different directions.
2) Lightly head secondaries (about 15–25%) to outward buds for balanced branching.
3) Keep the center open; thin inward/upright, crossing, and shading branches.
- Summer:
1) Light green pruning to remove watersprouts/suckers and preserve internal light.
2) Maintain angles and prevent overly upright secondaries.
Year 4
- Winter:
1) Structure is nearly complete; if needed, build 1–2 tertiaries per secondary in gaps only.
2) Control height and spread: use reduction cuts to outward laterals rather than blind heading to preserve open form and balanced height.
3) Thin shading and rubbing wood; keep the center open.
- Summer:
1) Minimal green pruning; remove watersprouts and maintain internal light.
Year 5
- Winter:
1) Enter maintenance phase: remove about 10–15% of wood annually (targeted thinning, not heavy heading).
2) Remove inward/crossing, dead or diseased wood; keep canopy open and balanced.
3) Males can be pruned a bit harder with light heading to increase one-year-old wood for pollen; females more gently to preserve fruiting wood.
- Summer:
1) Control upright watersprouts and basal suckers; keep the center open.
Pro cutting technique
- Cut just outside the branch collar; don’t leave stubs.
- Use the three-cut method on thick limbs to prevent bark tearing.
- Disinfect tools between trees (and between cuts on infected trees) with 70% alcohol or 0.5–1% sodium hypochlorite.
- Prune in dry weather; in humid regions only in 2–5 day dry windows. After opening the canopy, whitewash interior branches exposed to sun.
Common errors (and fixes)
- Heavy heading in years 2–3 → use light heading plus reduction cuts; focus on thinning.
- Tight scaffold angles → set angles with clips/spreaders from year 1.
- Closing the center with upright shoots → remove competitors/uprights inside the canopy yearly.
- Heavy autumn pruning → do main work in late winter; autumn only for sanitation.
Practical guide to preventing post-pruning fungal infections (pistachio)
Golden rules
- Prune dry: only during 2–5 day rain-free, low-fog windows; keep cuts dry for the first 48–72 hours.
- Make proper cuts: thinning rather than heavy heading; cuts at the branch collar without stubs; three-cut method for big limbs.
- Tool hygiene: clean blades + frequent disinfection between trees (and between cuts on infected trees).
- Manage debris: remove infected wood from the orchard and destroy; don’t leave inoculum in place.
- Protect large wounds: on cuts >3–4 cm in high-risk orchards, use approved wound protectants/pastes.
- No overhead wetting: avoid any irrigation that wets foliage for 2–3 days after pruning.
- Monitor: inspect wounds 2–6 weeks later for canker symptoms.
Step-by-step checklist
1) Timing and work order
- Choose late winter, after frost and before bud swell, on sunny/dry days.
- Humid climates: work midday (lower humidity) and only in dry windows; stop if rain returns.
- Sequence: healthy blocks → suspect → infected. Disinfect tools/gloves when entering each block.
2) Cut technique and risk reduction
- Cut at the branch collar without stubs; don’t strip bark (use the three-cut method on heavy limbs).
- Keep cut diameters as small as possible; minimize cuts >3–4 cm.
- Prefer thinning (removing the whole offending branch) over heading (shortening), which creates many wounds and watersprouts.
- On dead/diseased wood, cut 20–30 cm below discolored tissue.
3) Tool disinfection
- Physical cleaning first: remove sap/soil with a brush/cloth; disinfectants don’t work on dirty blades.
- Reliable options and contact time:
- 70% alcohol (ethanol/isopropyl): spray/dip to wet thoroughly; ≥30 seconds.
- 0.5–1% sodium hypochlorite: make 10–20% solution of 5% household bleach; 1-minute contact. (Corrosive to metal—rinse and oil blades at day’s end.)
- Quaternary ammonium compounds (QACs): per label (typically 0.1–0.3%) and contact time.
- Frequency: between trees; on infected trees, between cuts.
- Solution management: replace every 1–2 hours or when cloudy. Alcohol is flammable—keep away from ignition.
4) Debris management
- Remove cankered/infected wood from the orchard and burn, or compost hot (≥55–60°C for several consecutive days).
- Chipping and leaving in place is for healthy wood only and mainly in dry climates; in humid areas it can become inoculum.
- Collect and remove last year’s mummies and dried fruiting twigs.
5) Wound protection and aftercare
- Small cuts: typically don’t need sealants; keeping them dry is best.
- Large cuts (>3–4 cm) or orchards with heavy Botryosphaeria/Cytospora history:
- Paint wound edges with diluted white latex (1:1 with water) to reduce sunscald/cracking; not a fungicide, but reduces stress and secondary cracking.
- Where permitted and disease pressure is high, use approved pastes/paints containing copper or labeled fungicides (e.g., thiophanate-methyl) on large cuts
, strictly per label. Avoid non-breathable tars/adhesives that trap moisture.
- Protective spray: in high-risk, humid orchards, a copper spray (e.g., copper oxychloride/hydroxide) within 24 hours after pruning, applied in dry weather,
can lower surface infection risk. Always follow product labels and local regulations.
6) Moisture and water stress management
- For 48–72 hours, avoid irrigation that wets the canopy (overhead/micro-sprays that reach foliage).
- Keep the canopy open and ventilated so cuts dry quickly.
- After heavy pruning, temporarily reduce nitrogen so you don’t stimulate lush, tender watersprouts.
7) Post-pruning monitoring
- Recheck large wounds 2–6 weeks later: blackening margins, gumming, radial cracks, or dieback are red flags.
- If seen, recut 20–30 cm below infected tissue; disinfect tools between cuts; remove the wood from the orchard promptly.
Climate notes
- Humid regions: higher sensitivity; more frequent disinfection, shorter dry windows, wound protection on large cuts, complete removal of infected debris.
- Dry regions: lower disease risk but higher sunscald risk after opening the canopy; interior whitewashing is very important.
Guide to choosing pruning tools and blades for pistachio
- For live wood: bypass hand pruners + tri-edge hand saw; SK5 carbon steel blades with anti-stick coating.
- For dead/thick wood: long-handled bypass lopper (to 35–45 mm); above that, a 27–33 cm pruning saw or a pole saw.
- Large orchards: battery-electric or pneumatic pruners greatly boost productivity (with training and proper safety).
- Humid climates: prioritize PTFE or hard-chrome coatings + frequent disinfection; ventilated sheaths and dry storage.
Tool categories and suggested specs
| Tool | Primary use | Recommended capacity | Key features |
| --- | --- | --- | --- |
| Bypass hand pruners | Live wood, small branches | Up to 20–25 mm | Curved bypass blade, forged SK5 steel, sap groove, PTFE/chrome coating, ergonomic
handles (sized), adjustable center bolt, shock absorber |
| Anvil hand pruners | Dead wood | Up to 20–25 mm | For dead wood only; crushes live tissue |
| Bypass lopper (long-handled) | Medium branches | Up to 35–45 mm | Bypass head, 45–75 cm handles (preferably telescopic), geared/compound leverage, replaceable blade, strong bumper |
| Hand pruning saw | Branches >30–40 mm | 27–33 cm blade | Tri-edge teeth, pull-cut action, curved blade for overhead, induction-hardened teeth, hook tip for control, belt sheath |
| Pole saw/pruner | Out-of-reach branches | Up to 6–8 cm | 3–4 m fiberglass pole, secure joints, 33–37 cm curved blade; small rope-head pruner only for twigs |
| Battery-electric pruners | Speed in large blocks | 25–45 mm (model-dependent) | 14–36 V batteries, bypass blade, safety lock, cut-resistant gloves; training required |
| Pneumatic pruners | Professional crews | 25–35 mm | Light and fast; needs PTO compressor/hoses; hose management in-row |
| Light chainsaw (pro) | Very thick/dead limbs | >10 cm | Top-handle 12–14 in bar, semi-chisel low-kickback chain; trained operator only |
Blades: types and geometry
- Bypass for live wood: clean cuts with minimal crushing of phloem/cambium—default choice for pistachio.
- Anvil for dead wood: suitable for dead material; crushes live wood and slows healing.
- Steel and heat treatment:
- Forged SK5 or Cr-V carbon steel: holds an edge and can be field-sharpened.
- PTFE/hard chrome coatings: reduce friction and sap sticking (very useful in humid climates).
- Edge angle: 20–25° for durability on pistachio’s relatively hard wood; a 2–3° micro-bevel increases longevity.
- Saw blades:
- Tri-edge teeth, pull-stroke cutting, 3–4 mm tooth pitch (~7–8 TPI) for live wood; slightly coarser pitch for very dry wood.
- Curved blades improve overhead control; straight blades cut more precisely near collars at low height.
- Induction-hardened teeth are typically non-sharpenable; replace the blade when dull.
Suggested kits by task
- Training (years 1–3, open vase)
- Bypass hand pruners sized to hand (20–25 mm capacity, rotating handle if heavy use).
- Light 60–70 cm bypass lopper for 25–40 mm competitors.
- 27 cm curved hand saw with belt sheath.
- Annual maintenance of bearing trees
- Bypass hand pruners + telescopic bypass lopper.
- 30–33 cm hand saw (spare blade).
- 3–4 m pole saw for interior overhead branches (reduces ladder use).
- Professional/large orchards
- 1–2 battery-electric pruners with two spare batteries and field charger.
- Modular fiberglass pole saw + hand saw with spare blade.
- Disinfection kit (70% alcohol or 0.5–1% hypochlorite), tool belt, quality sheaths.
Care, sharpening, and calibration
- Cleaning: after each shift, remove resin/dust with warm water and mild detergent or a light solvent; dry and lightly oil pivots and blades.
- Disinfection during work: between trees (and between cuts on diseased trees) with 70% alcohol or 0.5–1% hypochlorite; contact time 30–60 seconds.
- Sharpening: daily or whenever cuts crush/tear.
- Pruners/loppers: 300–600 grit diamond file/stone; work only the outer bevel at 20–25°; deburr with 2–3 light passes on the flat back.
- Saws with hardened teeth: replace blade; non-hardened can be filed (specialist job) with a triangular file.
- Adjustments: tighten the center bolt to remove play while keeping smooth motion; replace worn bumpers and springs.
Safety and ergonomics
- Cut-resistant gloves and safety glasses; high-ankle footwear. For overhead work, a light helmet helps.
- Use an aluminum tripod orchard ladder on firm ground; never work on soft mud or steep slopes.
- Choose handle size to fit your hand (right-/left-handed models exist). Rotating handles reduce tendon strain.
- Always sheath saws and pruners to prevent cuts and keep blades dry.
Climate tips
- Humid: anti-stick coatings, ventilated sheaths, frequent disinfection, don’t store tools wet in sheaths.
- Dry/dusty: frequent dusting and light oiling of pivots; harder steels (SK5) keep an edge longer.
Mechanized pruning equipment for pistachio + indicative throughput, savings, and labor needs
Levels of automation (from assist tools to heavy mechanization)
- L1 – Powered assists: battery-electric pruners, pneumatic pruners (PTO compressor), battery-powered pole saws.
- L2 – Platforms and logistics: self-propelled or tractor-towed orchard platforms for multi-person ladder-free work; mechanized residue collection and
in-row chipping/shredding (PTO).
- L3 – Row mechanical cutting: tractor-mounted hedgers/toppers (circular saw blades or bar saws) to reshape the canopy, followed by selective touch-up pruning.
- L4 – Emerging/exploratory: selective pruning robots with machine vision (not yet widely commercial in pistachio).
Summary of performance and savings (indicative; varies with age, intensity, spacing)
| Equipment category | Application | Typical field capacity | Manual labor savings | Uptime | Notes |
| --- | --- | --- | --- | --- | --- |
| Battery-electric pruners | Selective pruning of live wood up to 25–45 mm | 1.5–2.0× manual speed | 25–40% fewer person-hours | 85–95% (with 2 batteries/shift) | Less fatigue; training and safety essential |
| Pneumatic pruners + PTO compressor | Similar to above; larger crews | Near electric | 20–35% | 65–85% (hose management downtime) | Best for long rows or semi-fixed stations |
| Battery/petrol pole saws | Removing overhead limbs 60–120 mm | +0.2–0.4 ha/person/shift | 10–20% (with powered pruners) | 80–90% | Reduces ladder moves |
| Self-propelled/towed platforms | Safe, fast multi-person access | 0.3–0.6 ha/shift/team | 15–30% on overhead work | 70–85% | Eliminates ladder time; more uniform quality |
| Tractor hedger/topper (disk/bar saw) | Row-side and top trimming | 0.8–1.6 ha/machine-hour | 30–60% (with touch-up) | 60–75% | For row orchards with uniform canopies; be cautious with classic open-vase pistachio |
| PTO in-row chipper/shredder | In-place residue shredding | 1.0–2.5 ha/machine-hour | 50–80% on collection/hauling | 70–90% | Reduces passes and traffic; produces mulch |
| Windrower/rake for residues | Gathering prunings mid-row | 0.8–1.5 ha/hour | 30–50% cleanup savings | 70–85% | Often precedes in-row chipping |
| Mobile PTO compressor | Powers 3–6 pneumatic pruners | — | — | 85–95% | Cost-effective for large crews |
Person-hour model (illustrative)
- Baseline assumption: medium pruning intensity; manual pruning ≈ 100 person-hours/ha; cleanup/collection ≈ 30 person-hours/ha; total = 130 person-hours/ha.
- Scenario A (battery pruners): pruning −30% → 70 + cleanup 30 = 100 person-hours/ha (≈23% total savings).
- Scenario B (battery pruners + platform): pruning −50% → 50 + cleanup 30 = 80 person-hours/ha (≈38% savings).
- Scenario C (battery pruners + in-row chipper): pruning −30% → 70 + cleanup 10 = 80 person-hours/ha (≈38% savings).
- Scenario D (hedger + touch-up + chipper): touch-up 30–50 person-hours/ha + chipper 10 + hedger 1–2 machine-hours/ha → equivalent 40–60 person-hours/ha
+ 1–2 machine-hours/ha (≈54–69% manual labor savings vs. baseline).
Field notes for pistachio
- Mechanical hedging: in pistachio with irregular open-vase forms, indiscriminate hedging can cause watersprouts and short-term yield dips. If used, limit it to
“keeping canopy volume and machine clearance,” and follow with selective touch-up pruning.
- Best ROI often comes from combining battery pruners + in-row chipper plus a shared platform for the crew. In orchards >20–30 ha, payback of 1–3 seasons is
common (depends on local labor costs).
- Real uptime depends on row logistics, crew training, daily maintenance (sharpening/oiling/battery swaps), and dry weather windows.
Suggested implementation roadmap
1) Quick, low-cost: battery pruners for all cutters + disinfection kit + battery pole saw for overhead cuts.
2) Cut cleanup costs: in-row chipper/shredder + windrower/rake (when volume is high).
3) Crew productivity: one self-propelled or towed platform for ladder-free multi-person work.
4) Large, uniform blocks: tractor hedger/topper with a plan for targeted touch-up pruning.
Post-pruning strengthening tips to boost pistachio yield
Objectives after pruning
- Speed wound healing, control watersprouts, maintain internal light.
- Balanced nutrition for budbreak, bloom, and nut set.
- Moisture and hygiene management to prevent disease.
Timed checklist (0 to 60 days after pruning)
- Days 0–3
- Work only in dry weather; in orchards with canker/rot history, apply a protective copper spray per label.
- Whitewash interior, newly exposed wood with diluted white latex (1:1 with water).
- Avoid any irrigation that wets foliage.
- Weeks 1–2
- Keep irrigation “light and even”; avoid drought shocks and also heavy sets that trigger lush watersprouts.
- If pruning was “heavy,” reduce nitrogen 15–25% for 2–3 weeks to temper vegetative surge.
- Pre-bloom foliar spray (if needed): target micronutrients on unfolding leaves (details below).
- Weeks 3–6
- As nut set begins, introduce potassium through fertigation; small, steady doses beat heavy slugs.
- Light green pruning: remove upright watersprouts and basal suckers so resources go to nuts.
- Sanitation touch-ups: remove any newly dried or suspect twigs.
Nutrition and foliar spray guide (adjust to soil/leaf analysis)
- Nitrogen (N)
- After light/medium pruning: follow the usual plan in split applications from spring flush to mid-summer.
- After heavy pruning: reduce 15–25% for the first 2–3 weeks; then return gradually to normal. Too much N now = many tender watersprouts → shade and
reduced fruiting.
- Potassium (K)
- Key for nut size and fill. From early nut set to mid-summer, apply K (e.g., potassium nitrate/sulfate/thiosulfate) in small, continuous fertigation doses.
- Calcium and magnesium
- Adequate levels strengthen tissues and stress tolerance. In soft water, periodic calcium nitrate helps.
- Micronutrients (high-impact post-pruning)
- Zinc (Zn): common deficiency in pistachio; a pre-bloom Zn spray with a small amount of low-biuret urea supports new leaves and buds.
- Boron (B): aids buds and pollination pre-bloom; excess can be toxic—respect recommended rates.
- Iron/manganese: in calcareous soils, if chlorosis appears, use chelates suited to soil pH.
- Sample pre-bloom foliar mixes
- ZnSO4 0.5–1% + low-biuret urea 0.5–1% + boric acid 0.1–0.2% (apply before full bloom, in cool, calm weather)
- Notes: tank pH 5.5–6.5; avoid mixing with copper/phosphites in the same pass; always spot-test on a few trees first.
Irrigation after pruning
- Core principle: keep soil consistently moist without saturation; large moisture swings cause flower/fruit drop.
- Pruning intensity and first 2–3 weeks irrigation:
- Light (<10% wood removed): normal schedule.
- Medium (10–20%): ~10–15% less than usual, then ramp back.
- Heavy (>20–25%): ~15–25% less than usual; monitor growth; resume normal as leaf growth stabilizes.
- Avoid overhead/misting that wets foliage for 3–4 days.
Managing growth and light
- Keep the interior bright; remove any upright watersprout casting shade during green pruning.
- Preserve outward, wide-angled secondaries to carry next year’s one-year-old fruiting wood.
- Whitewash interior surfaces exposed to sun (after opening the canopy) to prevent sunscald and canker.
Hygiene and protection
- Disinfect tools during maintenance/green pruning (70% alcohol or 0.5–1% hypochlorite).
- Remove diseased debris from the orchard; chip and spread only healthy wood (critical in humid climates).
Common mistakes that reduce yield
- Rushing heavy nitrogen immediately after pruning → excessive watersprouts, shade, and reduced flowering.
- Water shocks (drought/saturation) during bloom and nut set → flower/fruit drop.
- Foliar sprays without spot-testing and pH control → leaf/flower burn.
- Leaving large cuts unprotected from sun after opening the canopy → sunscald and disease.
