S4ag Small Fruits

---
name: s4ag-small-fruits
description: "Help with berries, brambles, currants, canes, and vines. Use when the user asks about blueberries, strawberries, raspberries, blackberries, gooseberries, currants, grapes, or any small fruit establishment, pruning, disease, or harvest."
allowed-tools: [Read]
---

# Small Fruits

Small fruit production — berries, brambles, currants, canes, and vines — rewards careful establishment and pays you back across many seasons from the same planting. Get the variety, site, and soil biology right at the start and these crops become lower-maintenance over time; get them wrong and each season is a fight. The underlying principle: small fruits are perennial, and perennials run on fungal-dominated soil biology. Every management decision should be assessed against whether it builds or destroys the mycorrhizal networks these crops depend on.

**How this skill works:** Each sub-tool pauses at a **Checkpoint** to confirm the assumptions it is about to build on before producing output. A recommendation built on a wrong assumption wastes time and money — confirm the checkpoint before acting. Each sub-tool ends with **Next steps** — the skills worth running once you have acted on this one.

---

## Expert Lineage

*The thinkers whose frameworks underpin this skill — and what they specifically discovered that changes how you farm.*

**Lewis Hill — Small Fruit Horticulture in Practice**
Hill's foundational observation: most small fruit failures happen in the first season, and most first-season failures trace to poor site preparation and wrong variety selection rather than poor management. His specific contribution is the systematic pre-planting checklist — drainage, pH, sunlight hours, wind exposure, and varietal chill-hour matching — that prevents the majority of establishment losses before a plant goes in the ground. Implication: spend 80% of your planning time before planting, not after.

**Lee Reich — Expanding Small Fruit Diversity**
Reich documented the productivity and disease resistance of underused small fruit species — jostaberry, aronia, cornelian cherry, serviceberry, goumi — that outperform mainstream varieties in difficult conditions. His specific finding: many of the most reliable small fruits are also among the most mycorrhizal-dependent, thriving with minimal inputs on functioning biology while collapsing under chemical fertility programmes that bypass the food web. Implication: species selection is risk management, not just flavour preference.

**Michael Phillips — The Mycorrhizal Foundation of Small Fruit Health**
Phillips, working from his Lost Nation Orchard in New Hampshire, demonstrated that fungal networks are the primary determinant of disease resistance in berry and vine crops. His most actionable finding: the standard commercial strawberry protocol — fumigation, black plastic, annual replanting — severs every mycorrhizal connection the plant could form, producing yield in year one but requiring progressively more inputs each season. Permanently mulched, non-fumigated systems with active fungal networks outperform them by year three. Implication: every fungicide application has a soil biology cost that compounds over time.

**Elaine Ingham — Soil Food Web and Mycorrhizal Dependency**
Ingham's research established that blueberries, raspberries, and strawberries rank among the most mycorrhizal-dependent crops in temperate agriculture. Her key finding relevant to small fruits: ericoid mycorrhizal fungi (required by blueberries) are highly sensitive to synthetic nitrogen and phosphorus — excess soluble fertility destroys the fungal partnership, making the plant structurally dependent on purchased inputs. The practical implication is that blueberry nutrition programmes built around slow organic fertility and active soil biology consistently outperform high-input conventional programmes on three-to-five year timeframes.

**Christine Jones — Root Exudates and Perennial Productivity**
Jones demonstrated that perennial crops with undisturbed root systems pump 30–40% of photosynthate directly into fungal networks as exudates. The practical application for small fruits: cultivation between rows, herbicide use in the root zone, and black plastic mulch all disrupt this exudate-to-fungi pathway. Wood chip mulch, permanent sward between rows managed low, and minimal soil disturbance maintain the pipeline. Implication: weed management strategy in a small fruit system directly determines long-term productivity.

**Eliot Coleman — Season Extension and Crop Health through System Integrity**
Coleman's contribution to small fruit management is the principle that crop health problems are almost always system problems — not isolatable pest or disease events. His work on elicitors (foliar kelp, silica, biostimulants) to build plant systemic resistance maps directly onto small fruit disease management: a plant with high Brix and good mineral balance resists Botrytis and mildew at a cellular level. Implication: foliar feeding for resistance is more effective and cheaper than reactive fungicide applications.

---

## Which tool fits

| You need to... | Tool |
|---|---|
| Choose species and varieties for your site and market | variety-selection |
| Prepare site and establish a new planting | establishment |
| Select a training system and prune correctly | training-and-pruning |
| Manage fertility and soil biology for small fruits | nutrition-and-soil |
| Identify and manage pests and diseases | pest-and-disease |

## Routing Decision

- **Starting from scratch — don't know what to plant** → variety-selection
- **Have a variety chosen, planning to plant this season** → establishment
- **Established planting that needs pruning or trellising decisions** → training-and-pruning
- **Crops performing poorly — yellowing, poor yield, stunted growth** → nutrition-and-soil
- **Visible damage, spots, lesions, insects, or wilting** → pest-and-disease
- **Unsure** → variety-selection first; it establishes the baseline for everything else

---

## Variety Selection

*Matches species and cultivar to your climate, site, market, and disease pressure — before any money is spent.*

Work through the selection sequence in this order. Changing variety after planting is expensive; changing it before costs only time.

**Step 1 — Establish which species the site will support.**

| Site condition | Suited species | Poor fit |
|---|---|---|
| pH 4.5–5.5, well-drained, high OM | Blueberry (highbush or rabbiteye) | Raspberry, gooseberry |
| pH 6.0–7.0, fertile, good moisture | Strawberry, raspberry, blackcurrant | Blueberry |
| Heavy clay with drainage | Blackcurrant, gooseberry | Strawberry, blueberry |
| Exposed, windy site | Gooseberry, jostaberry, aronia | Grape, raspberry |
| Warm, sheltered microclimate | Grape, fig, hybrid berries | Gooseberry (sulks in heat) |
| Frost pocket | Avoid early-flowering species | Strawberry (early vars), grape |

**Step 2 — Chill hours.** Most small fruits require a minimum of dormancy (cold hours below 7°C) to fruit reliably. Check the expected annual chill hours for your site.

| Species | Chill hour requirement (approx.) |
|---|---|
| Highbush blueberry | 800–1,000 hours |
| Rabbiteye blueberry | 400–600 hours (warmer climates) |
| Strawberry (June-bearing) | 200–400 hours |
| Raspberry | 800–1,600 hours |
| Gooseberry / blackcurrant | 800–1,000 hours |
| Grape (most table/wine varieties) | 100–500 hours |

**Step 3 — Prioritise disease resistance.**
In humid climates, disease-resistant varieties eliminate the majority of spray decisions before they arise. Key diseases by species:

- Strawberry: Verticillium wilt, Botrytis (grey mould), Phytophthora crown rot. Choose resistant or tolerant varieties; avoid Verticillium-susceptible varieties on soils with history of strawberries or potatoes.
- Raspberry: Phytophthora root rot (prioritise in heavy soils), cane diseases. Primocane varieties (autumn-bearing) often escape spring-borne disease pressure by fruiting later.
- Blueberry: mummy berry, powdery mildew. High-bush varieties vary significantly in susceptibility — check regional trial data.
- Currants/gooseberries: powdery mildew is the primary concern in humid conditions. Resistant varieties (Ben Sarek, Ben Hope, Hinnonmäki) transform management.
- Grapes: Botrytis, downy mildew, powdery mildew. Hybrid varieties bred with Vitis rupestris / labrusca parentage carry dramatically better disease resistance than vinifera for humid climates.

**Step 4 — Match season to market and labour.**
- Staggered varieties (early/mid/late season) spread the harvest window and reduce labour peaks.
- June-bearing strawberries give concentrated commercial harvests; everbearing varieties give smaller daily picks over a longer period — better for farm stand or U-pick.
- Primocane (autumn) raspberries simplify cane management: cut everything to ground in winter.

**Step 5 — Cross-pollination requirements.**
- Blueberries: plant at least two compatible varieties for reliable set. Rabbiteye blueberries require cross-pollination.
- Gooseberries: self-fertile; single variety will crop.
- Currants: most are self-fertile; cross-pollination improves yield.
- Grapes: most wine and table varieties are self-fertile; some require a polliniser — check the specific variety.

**Checkpoint — confirm before finalising:**
- What is the soil pH on the intended site? (Critical for blueberries; determines species viability.)
- What is the primary market or use — fresh direct sale, U-pick, processing, household? This determines season length priorities.
- What is the climate zone and typical summer humidity level? Humidity determines how heavily disease resistance should be weighted.

Recommending a blueberry variety without knowing pH, or a Vitis vinifera grape in a high-humidity region without flagging the disease implications, produces an expensive mistake.

**Output:**
```
SMALL FRUIT VARIETY RECOMMENDATION

Site summary:
  pH: [value]
  Climate zone / region: [zone]
  Summer humidity: [low / moderate / high]
  Market or use: [fresh / u-pick / processing / household]

Recommended species: [species]
Recommended varieties:
  Primary: [variety name] — [reason: disease resistance / season / yield]
  Secondary: [variety name] — [reason: pollination partner / season extension]
  Optional: [variety name] — [reason]

Cross-pollination required: [yes / no / note]

Disease risks to monitor in this climate:
  - [disease 1]
  - [disease 2]

Species to avoid for this site and why:
  - [species]: [reason]
```

**Next steps:**
- Run establishment (within this skill) to prepare the site correctly for the chosen species.
- `/s4ag-soil` — run test-interpretation if pH and soil biology status are unknown; blueberries especially require precise pH and active fungal biology.
- `/s4ag-pests` — review the disease profile for chosen varieties before establishing, not after first infection appears.

---

## Establishment

*Prepares the site and plants for a productive, long-lived planting — the decisions made here determine performance for 10–30 years.*

Small fruits are among the most sensitive crops to establishment conditions. The cost of a poor establishment — replanting, lost seasons, persistent disease — is far greater than the cost of doing it right the first time.

**Establishment sequence:**

**1. Soil preparation — 6–12 months before planting.**

Test soil pH and OM before anything else.

| Species | Target pH | OM target | Key soil note |
|---|---|---|---|
| Blueberry | 4.5–5.5 | >4% | Needs active ericoid mycorrhizae; acidify with sulphur, not chemicals |
| Strawberry | 6.0–6.5 | >3% | Excellent drainage essential; raised beds in heavy soils |
| Raspberry / blackberry | 6.0–6.5 | >3% | Deep, non-compacted soil; roots to 60cm |
| Currant / gooseberry | 6.0–7.0 | >3% | Tolerant of moderate clay; avoid waterlogging |
| Grape | 5.5–7.0 | >2% | Prefers lean mineral soil; excess fertility reduces quality |

To lower pH for blueberries: apply elemental sulphur at least 6–12 months before planting. Rate: approximately 200–400 g/m² to drop pH by 1 unit in loam — test again before planting. Do not use aluminium sulphate — it kills soil biology.

**2. Drainage.**
Standing water for more than 24 hours after rain will kill most small fruit roots. Check drainage before committing. Solutions:
- Raised beds (30–40cm high) for strawberries on heavy soil — double benefit of drainage and warming.
- Mole draining or tile drainage for raspberries and currants on clay.
- For blueberries: raised planting mounds 20–30cm above grade where drainage is marginal.

**3. Mycorrhizal inoculation.**
This is the single highest-value biological intervention at planting:
- Blueberries require ericoid mycorrhizal fungi (Hymenoscyphus ericae) — not the same as the AM fungi used for most other crops. Source a dedicated ericoid inoculant.
- Raspberries, strawberries, currants, and grapes use arbuscular mycorrhizal (AM) fungi. Apply directly to roots or into the planting hole.
- Do not use soluble phosphorus fertiliser in the planting hole — excess P suppresses mycorrhizal colonisation.

**4. Planting.**

Timing by species:
- Bare-root plants: plant in dormancy, late autumn to early spring. Do not let roots dry out — heel in immediately if not planting within 24 hours.
- Container plants: plant spring or early autumn; avoid summer planting unless irrigation is reliable.

Spacing:

| Species | Within-row spacing | Between-row spacing |
|---|---|---|
| Highbush blueberry | 1.2–1.5m | 2.5–3m |
| Strawberry | 30–40cm | 60–90cm |
| Raspberry (cane) | 45–60cm | 1.8–2m |
| Blackcurrant | 1.5–2m | 2–2.5m |
| Gooseberry | 1.2–1.5m | 1.5–2m |
| Grape (trained) | 1.5–2m | 2.5–3m |

**5. Mulching.**
Apply 10–15cm of wood chip mulch immediately after planting for all species. Exceptions:
- Strawberries: use straw mulch around plants, not over crowns. Wood chips suppress the runners needed for plant establishment in year one.
- Grapes: minimal mulch in the root zone until established; excessive moisture retention can encourage root disease in poorly-drained soils.

Wood chip mulch feeds fungal networks, suppresses weeds without herbicide, and moderates soil moisture — three management problems solved with one input.

**6. Irrigation in establishment year.**
All small fruits need consistent moisture in the first season while roots establish. Drip irrigation is preferred — it keeps foliage dry (reducing disease) while maintaining root zone moisture. Target: keep soil consistently moist but not waterlogged for the first full growing season.

**7. First-year management.**
- Remove blossoms in year one (strawberries, blueberries) — this redirects energy into root and plant development and pays back in years 2 and 3.
- Pinch out runners on strawberries if plant establishment rather than runner production is the goal.
- For raspberries: cut canes back to 20–30cm at planting; this forces strong basal growth.

**Checkpoint — confirm before finalising:**
- Has the soil pH been tested and adjusted if needed? (Blueberries in wrong pH will never perform regardless of other management.)
- Is drainage adequate, or does it need addressing before planting?
- Is irrigation available for the establishment year? Lack of irrigation in year one is the second most common cause of establishment failure after wrong pH.

Planting into unadjusted pH or unresolved drainage — even with perfect subsequent management — produces a struggling planting.

**Output:**
```
ESTABLISHMENT PLAN

Species: [species]
Site: [drainage status / pH / OM]

Pre-planting soil work:
  pH adjustment: [product / rate / timing]
  OM amendment: [compost / rate / timing]
  Drainage improvement: [action required / none]

Planting:
  Source: [bare-root / container]
  Planting window: [months]
  Spacing: [within-row x between-row]
  Mycorrhizal inoculant: [product type / application method]

Establishment year management:
  Irrigation: [drip / hand water / schedule]
  Mulch: [type / depth]
  First-year actions: [remove blossoms / pinch runners / cut back]

Expected first productive harvest: Year [2 / 3]
```

**Next steps:**
- Run training-and-pruning (within this skill) to plan the support structure and first-year training regime.
- `/s4ag-soil` — if pH adjustment is needed, run amendment-planning for accurate sulphur rates.
- `/s4ag-water` — if irrigation is needed and a system does not exist, plan it before planting, not after.

---

## Training and Pruning

*Selects the right training system and provides the annual pruning methodology for each small fruit species.*

Training and pruning decisions are species-specific and system-specific. Running this sub-tool without knowing the species produces generic advice that may actively harm the planting.

**Strawberries — system selection and management**

Three production systems:

| System | Description | Best for |
|---|---|---|
| Matted row | Runners fill between plants; harvest entire row | Large-scale, low-labour |
| Hill system | Runners removed; individual plants maintained | High-density market, raised beds |
| Raised table-top | Elevated beds, substrate growing | Eliminating fumigation; reduced bending |

Annual management:
- After fruiting: mow foliage to 8–10cm above crowns (do not damage crowns). Remove mowings.
- In matted row: renovate row width to 30–40cm; remove excess plants.
- Replace planting on 3–4 year cycle to manage virus and disease buildup.

**Raspberries — floricane vs. primocane**

The critical distinction:
- Floricane (summer) varieties: fruit on second-year canes. Prune out fruited canes immediately after harvest; leave new green canes to overwinter.
- Primocane (autumn) varieties: fruit on current season's growth. Cut all canes to ground in late winter — single clean management decision.

Training system: single or double wire at 60cm and 120cm height. Tie canes loosely — do not restrict growth.

Annual management for floricane types:
1. Immediately after summer harvest: remove all fruited canes (dark, woody, with spent laterals) at ground level.
2. Thin remaining new canes to 6–8 per metre of row. Remove weakest.
3. Tip canes at 1.5–1.8m if exceeding trellis height.
4. Late winter: remove any winter-damaged tips.

**Blackberries and hybrid berries**

Similar management to floricane raspberries. Key differences:
- Canes are more vigorous — typically 2.5–4m. Fan train along wires to manage.
- Tip-rooting varieties (most blackberries) require management to prevent runners establishing where not wanted.
- Thornless varieties sacrifice some vigour for handling ease.

**Blackcurrants**

Prune for maximum new wood each season — blackcurrants fruit best on one-year-old wood.

Annual pruning (late winter):
1. Remove all canes more than 3 years old (dark, very woody, few side shoots) — cut to base.
2. Remove any weak or crossing canes.
3. Aim to retain approximately 6–8 strong canes of mixed ages; at least half should be one-year-old growth.

Renovation of neglected bushes: hard cut to 15–20cm from ground in late winter. Lose one season; regain a productive plant.

**Gooseberries and redcurrants**

These fruit on spurs on older wood and on one-year shoots — different from blackcurrants.

Training systems:
- Open goblet bush: most common; 5–6 main framework branches; open centre for light and air.
- Cordon (single, double, or triple): wall or fence trained; high-density, easier pest and disease management.

Annual pruning:
1. Summer: tip all new side shoots to 5 leaves (gooseberry, redcurrant). Improves fruit quality and airflow.
2. Winter: cut tipped side shoots back further to 2–3 buds from their base (forming fruiting spurs).
3. Extend framework branches by leaving the leader of each branch unpruned or lightly tipped.

**Blueberries**

Slow to establish; do not prune hard in first 3 years. Allow the plant to build framework.

From year 4:
1. Remove the oldest, thickest canes (darkest, most woody, least productive) — take out 1–3 per bush per year.
2. Remove twiggy, thin growth from the base — it will not carry useful fruit.
3. Open the centre of the bush to light and air.
4. Retain 6–8 strong framework canes of mixed ages.

**Grapes**

Grape pruning is the most technically demanding of the small fruit group. System selection determines pruning method.

Two main systems:
- Spur pruning (Guyot, bilateral cordon): suitable for most table grapes and many wine varieties.
- Cane pruning (single or double Guyot): preferred where fruitfulness of basal buds is low; most standard wine variety management.

Guyot system annual management:
1. In late autumn/early winter (when dormant), cut back the previous year's fruiting cane to the base.
2. Select two strong replacement canes from the base of the plant.
3. Bend one replacement cane horizontally along the lower wire — this is the new fruiting cane.
4. Cut the second replacement cane to 2–3 buds — this is the replacement spur for next year.
5. Remove all other growth from the main trunk.

**Checkpoint — confirm before finalising:**
- What species and variety is being pruned? Cane management for floricane vs. primocane raspberries is opposite — doing the wrong one destroys the following season's crop.
- How old is the planting? Pruning a newly established planting the same way as a mature one stunts development.
- What training structure (wires, stakes, trellis) is in place or planned?

Pruning to the wrong system, or confusing floricane and primocane management, eliminates the next season's crop entirely.

**Output:**
```
TRAINING AND PRUNING GUIDE

Species: [species]
Variety type: [floricane / primocane / goblet / Guyot / etc.]
Plant age: [year of planting]
Training system: [description of physical support]

Annual pruning schedule:
  Timing: [month(s)]
  Step 1: [action]
  Step 2: [action]
  Step 3: [action]
  Retain: [number of canes / branches / spurs]
  Remove: [what to remove and why]

First year exceptions:
  [any departures from mature plant management]

Warning signs of wrong pruning:
  - [what poor outcome looks like]
```

**Next steps:**
- Run nutrition-and-soil (within this skill) — pruning stimulates new growth, which increases nutrient demand; confirm fertility is adequate.
- `/s4ag-pests` — immediately post-pruning is the best time to apply preventive biological treatments and identify overwintering disease.
- `/s4ag-composting` — apply compost or compost tea as a biological drench after pruning to support new root and shoot growth.

---

## Nutrition and Soil

*Manages fertility and soil biology for small fruits — the one domain where conventional and biological approaches diverge most sharply.*

Small fruits are perennial. The fertility decisions made in year one shape the soil biology the plant lives in for its entire productive life. Decisions that feel like "feeding the crop" are actually decisions about the food web.

**The mycorrhizal dependency problem**

Before any fertility recommendation, establish which fertiliser inputs are being considered and whether they will support or suppress the mycorrhizal network.

| Input | Food web effect | Note |
|---|---|---|
| Soluble NPK (liquid, high concentration) | Suppresses mycorrhizae (high P most damaging) | Fast results, biology cost compounds over time |
| Slow-release granular organics (feather meal, bone meal, rock minerals) | Neutral to positive | Mineralises via biology; feeds the food web |
| Compost (low C:N) | Builds bacterial population; supports biology | Best applied as mulch layer, not incorporated |
| Wood chip mulch | Builds fungal networks directly | Primary tool for perennial small fruit systems |
| Fungicide applications | Destroys mycorrhizal fungi | The most damaging single input in small fruit systems |
| Synthetic herbicide (root zone contact) | Disrupts root-exudate-to-fungi pathway | Particularly damaging for blueberry, raspberry |

**Nutrient requirements by species**

| Species | N demand | pH requirement | Key deficiencies to watch |
|---|---|---|---|
| Blueberry | Low–moderate | 4.5–5.5 | Iron (chlorosis at wrong pH), manganese |
| Strawberry | Moderate | 6.0–6.5 | Potassium (poor colour/flavour), calcium (tip burn) |
| Raspberry | Moderate | 6.0–6.5 | Magnesium (interveinal chlorosis), nitrogen (weak canes) |
| Blackcurrant | Moderate–high | 6.0–7.0 | Potassium (scorch), nitrogen (small leaves, weak growth) |
| Gooseberry | Low | 6.0–7.0 | Potassium (scorch), magnesium |
| Grape | Low | 5.5–7.0 | Boron (poor set), magnesium (chlorosis) |

**Blueberry nutrition — specific protocol**

Blueberries require the most careful fertility management of any small fruit:
1. Never use conventional ammonium nitrate or urea — they damage ericoid mycorrhizae and spike pH.
2. Nitrogen source matters: ammonium sulphate (if conventional) acidifies as it fertilises — acceptable in small doses. Best option: blood meal or feather meal worked into the mulch layer.
3. pH maintenance is a continuing task: if pH drifts above 5.5, plants show iron chlorosis (young leaves yellow between veins). Annual elemental sulphur applications maintain pH long-term.
4. Ericoid mycorrhizal inoculant: apply annually for the first three years; once established, maintain by never using inputs that destroy them.

**Foliar programme for disease resistance**

Eliot Coleman's work on elicitors applies directly here. A foliar programme builds systemic resistance more cost-effectively than reactive sprays:
- Liquid kelp (seaweed extract): apply 2–4 times from bud break through mid-season. Stimulates plant immunity and Brix.
- Soluble silica: strengthens cell walls; reduces susceptibility to Botrytis and powdery mildew.
- Compost tea (aerated): foliar application at bud break and post-harvest colonises leaf surface with beneficial organisms that outcompete disease organisms.
- Fish hydrolysate: biostimulant that increases root activity and plant vigour.

This programme does not eliminate all disease pressure but dramatically reduces it, often making fungicide applications unnecessary in all but the most humid seasons.

**Weed management and the soil biology trade-off**

The conventional approach — herbicide strip along the row — kills weeds efficiently but suppresses root exudate production and disrupts the mycorrhizal zone. Alternatives:
- Deep wood chip mulch (10–15cm): weed suppression comparable to herbicide in establishment; builds biology.
- Living mulch between rows (low grass or clover maintained short): provides biology while controlling bare-ground weeds.
- Flame weeding: effective on annual seedlings; does not damage soil biology when used judiciously.

**Checkpoint — confirm before finalising:**
- Is the system conventional (soluble inputs acceptable) or organic/biological? This determines the entire fertility table.
- What are the visible signs prompting the fertility question — weak growth, yellowing, poor fruit size, poor colour? The symptom routes to the deficiency.
- For blueberries specifically: what is the current pH, and when was it last measured?

Applying a general-purpose fertiliser to a blueberry with iron chlorosis caused by high pH achieves nothing — and high-N soluble inputs will make the pH problem worse.

**Output:**
```
NUTRITION PROGRAMME — [Species]

Current status:
  pH: [value / unknown]
  Visible symptoms: [description]
  System: [organic / conventional / transitioning]

Soil biology priority:
  Mycorrhizal status: [intact / unknown / likely damaged]
  Recommended inoculant: [type / timing]
  Mulch: [wood chip / straw — depth and application timing]

Fertility inputs:
  [Input]: [rate] [timing] [purpose]
  [Input]: [rate] [timing] [purpose]

Foliar programme:
  [Product]: [rate / dilution] [timing / frequency]

pH management (blueberries):
  Current pH: [value]
  Target pH: [4.5–5.5]
  Adjustment: [elemental sulphur at X g/m² — timing]

What to avoid:
  - [input to avoid and why]
```

**Next steps:**
- `/s4ag-soil` — run test-interpretation to baseline minerals before building the fertility programme.
- `/s4ag-composting` — supply the compost tea and biological amendment side of this programme on-farm.
- Run pest-and-disease (within this skill) — poor nutrition is often the underlying cause of disease susceptibility; address both together.

---

## Pest and Disease

*Identifies common small fruit problems and routes to the most effective management — IPM-first, least intervention.*

The IPM principle applies directly: identify before acting, set a threshold before spraying, choose the least disruptive effective intervention.

**The Ingham lens first**

Before diagnosing a specific pest or disease, ask whether the problem is a symptom of biology failure rather than an isolated pest event. A plant with poor nutrition and destroyed mycorrhizal networks is structurally vulnerable. Addressing the underlying biology reduces pest and disease pressure across all species — not by eliminating specific organisms, but by raising plant resistance above the threshold where opportunistic pathogens become problems.

**Common diseases by species and IPM ladder**

**Strawberries:**

| Disease | Symptoms | IPM ladder |
|---|---|---|
| Botrytis (grey mould) | Grey fuzzy mould on fruit, especially in wet conditions | 1. Improve airflow (wider spacing, remove old leaves); 2. Foliar silica + compost tea; 3. Bacillus subtilis (Serenade) if cultural controls fail; 4. Synthetic fungicide as last resort |
| Verticillium wilt | Plant collapses, crown brown on cross-section | Prevention only: disease-resistant varieties; no planting on Verticillium-infested ground. No curative option. |
| Phytophthora crown rot | Crown and roots rot; plant dies; wet soils | Drainage first; raised beds; Trichoderma inoculant on replanted sites |
| Powdery mildew | White powder on leaves, curling | Sulphur spray; potassium bicarbonate; neem oil; foliar silica prevents |

**Raspberries:**

| Disease | Symptoms | IPM ladder |
|---|---|---|
| Phytophthora root rot | Wilting despite moisture; roots brown and dead | Drainage is the cure; resistant varieties (Glen Ample, Tulameen less susceptible). |
| Cane blight / spur blight | Dark lesions on canes; dieback | Remove and burn affected canes; improve airflow; copper spray at budbreak if severe |
| Raspberry beetle | Grubs in fruit; adult weevil | Monitoring with pheromone traps; spray Bt (Bacillus thuringiensis) at petal fall; kaolin clay barrier |
| Botrytis | Mouldy fruit in wet harvest season | Remove mouldy fruit immediately; improve airflow; Bacillus subtilis |

**Blueberries:**

| Disease | Symptoms | IPM ladder |
|---|---|---|
| Mummy berry | Shrivelled, pale "mummified" fruit; shoots wilt in spring | Remove mummified fruit from soil surface; deep mulch covers apothecia; copper at budbreak on infected sites |
| Powdery mildew | White powder on leaves; late season | Sulphur (with caution — can damage blueberry foliage); potassium bicarbonate; neem |
| Phomopsis twig blight | Dying shoot tips in spring | Prune out affected growth; copper spray; improve drainage |
| Iron chlorosis | Young leaves yellow between veins | This is a nutrition problem (pH too high), not a disease. Lower pH. |

**Currants and gooseberries:**

| Disease | Symptoms | IPM ladder |
|---|---|---|
| American gooseberry mildew | White powder on young shoots and fruit | Resistant varieties first; potassium bicarbonate; sulphur; hard-prune affected material |
| Big bud mite (blackcurrant gall mite) | Swollen rounded buds in winter | Remove and burn affected buds; resistant varieties (Ben Hope); no chemical control reliably effective |
| Currant blister aphid | Red or yellow blisters on leaves; colonies underneath | Tolerance: rarely affects yield seriously; pyrethrum or insecticidal soap if severe |

**Grapes:**

| Disease | Symptoms | IPM ladder |
|---|---|---|
| Powdery mildew | White powder on leaves, shoots, and fruit | Sulphur (most important preventive); potassium bicarbonate; Bacillus subtilis |
| Downy mildew | Yellow patches on leaves above; white sporulation below | Copper (preventive, not curative); improve airflow; choose resistant varieties |
| Botrytis | Bunch rot; grey mould in tight clusters | Leaf removal around bunches (airflow); timing harvest before wet weather; Bacillus subtilis |

**Common pests across species:**

| Pest | Affected crops | Management |
|---|---|---|
| Vine weevil | Strawberry, blueberry (roots) | Nematodes (Steinernema kraussei in autumn); beneficial beetle habitat; no effective chemical for soil stage |
| Aphids (various) | All species | Beneficial habitat (hoverflies, parasitic wasps); pyrethrum if severe; insecticidal soap |
| Birds | All fruiting crops | Netting is the only reliable control |
| Spotted wing drosophila (SWD) | Raspberry, blueberry, strawberry, grape | Early-ripening varieties; harvest frequently; netting for high-value crops; kaolin clay |

**When to spray — decision rule:**
1. Can cultural controls (pruning, airflow, mulch, drainage) address this?
2. Is the damage threshold exceeded — is it affecting yield meaningfully?
3. What is the narrowest-spectrum effective biological intervention?
4. If a conventional spray is the answer: what is its biology impact, and is there a timing or application method that minimises it?

**Checkpoint — confirm before finalising:**
- What species and what specific symptom? Do not treat until identified — many common problems look alike.
- What is the current season and crop stage? Timing of some treatments (copper, Bt) is critical.
- Is this farm organic certified or using organic methods? This eliminates certain options and prioritises biological controls.

Spraying for Botrytis when the actual problem is iron chlorosis (or vice versa) wastes money and builds up chemical resistance for no benefit.

**Output:**
```
PEST/DISEASE DIAGNOSIS AND MANAGEMENT

Species: [species]
Symptom: [description]
Diagnosis: [probable cause]
Confidence: [high / moderate / low — if low, note what additional information is needed]

IPM RESPONSE SEQUENCE
Step 1 — Cultural control: [action]
Step 2 — Biological intervention: [product / timing / rate]
Step 3 — Organic/approved spray: [product / timing / rate — if steps 1-2 insufficient]
Step 4 — Conventional option: [product — note biology impact]

Preventive actions for next season:
  - [action 1]
  - [action 2]

What NOT to use (biology or resistance risk):
  - [input to avoid]
```

**Next steps:**
- Run nutrition-and-soil (within this skill) — if the disease is recurring despite treatments, weak plant biology is likely the root cause.
- `/s4ag-pests` — for complex or unresolved IPM decisions across multiple crops or a whole-farm pest pressure problem.
- `/s4ag-soil` — if the diagnosis points to systemic plant weakness (low Brix, poor vigour), the soil food web assessment comes before the spray programme.