Adding Pests & Diseases

Pests and diseases are defined in static Lua files under data/.

They apply negative effects to specific plant types and progress over time unless cured. These definitions are used by the growing system to apply random or conditional challenges to plants.

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Structure: Pests

A pest definition must include the following fields:

Field	Description
plant_types	Array of plant keys this pest can affect (e.g. "cabbage", "tomato")
label	Human-readable name
severity	Optional severity label (informational only)
effects	Tiered effect values applied per severity (low, medium, high)
cure	Required item to cure the pest (with id, label, and amount)
increase_rate	How fast the severity escalates (e.g. ticks until next stage)

Example: cabbage_loopers

cabbage_loopers = {
    plant_types = { "cabbage", "tomato", "corn" },
    label = "Cabbage Loopers",
    severity = "low",
    effects = {
        low = { quality = 2, health = 1 },
        medium = { quality = 4, health = 3 },
        high = { quality = 6, health = 5 }
    },
    cure = { id = "organic_pesticide", label = "Organic Pesticide", amount = 1 },
    increase_rate = 4
}

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Structure: Diseases

Diseases follow the exact same structure and fields as pests.

Example: downy_mildew

downy_mildew = {
    plant_types = { "cabbage", "tomato", "corn" },
    label = "Downy Mildew",
    severity = "low",
    effects = {
        low = { quality = 2, health = 1 },
        medium = { quality = 4, health = 2 },
        high = { quality = 6, health = 3 }
    },
    cure = { id = "copper_fungicide", label = "Copper Fungicide", amount = 1 },
    increase_rate = 5
}

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Effects Table

The effects table defines what penalties are applied to the plant per severity tier.

Each tier must include:

• quality: Reduction in final yield quality

• health: Reduction in overall plant health

These values are cumulative and applied when the condition escalates.

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Cure Field

The cure field defines which item is required to remove the pest or disease. Structure:

cure = {
    id = "item_name",
    label = "Item Label",
    amount = 1
}

This item must exist in your inventory system.

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Increase Rate

This value determines how quickly the condition escalates to a higher severity level. Lower values escalate faster.

increase_rate = 4 -- escalates every 4 ticks

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Registering New Pests or Diseases

To add a new entry:

1. Open data/pests.lua or data/diseases.lua.

2. Add a new key to the returned table.

3. Define the structure following the format above.

4. Ensure plant_types includes only valid keys from data/plants.lua.

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Example: Adding a New Disease

powdery_mildew = {
    plant_types = { "tomato" },
    label = "Powdery Mildew",
    severity = "low",
    effects = {
        low = { quality = 2, health = 1 },
        medium = { quality = 4, health = 2 },
        high = { quality = 6, health = 3 }
    },
    cure = { id = "sodium_bicarbonate", label = "Sodium Bicarbonate", amount = 1 },
    increase_rate = 5
}

Add this to the return table in data/diseases.lua. Pests follow the same format.