Disease is a condition that can afflict most crops grown through the Farming skill. When a healthy crop ends a growth cycle, there is a chance it may become diseased. While diseased, the crop stops growing and does not advance to the next stage. Crops do not recover from disease on their own, and die at the end of the diseased cycle if left uncured. Dead crops yield no experience and require use of a spade to dig up their remains before planting another crop in the patch.
Players may treat plants in diseased herb, flower, allotment, bush, hops, tree, fruit tree, hardwood tree, spirit, celastrus, belladonna, cactus, and mushroom patches with plant cure to restore the crop to health. Doing so may let the crop advance to the next growth stage normally upon the end of the cycle, although it is possible that it may become diseased again. For diseased trees and bushes, the player may use secateurs on the plant to trim the diseased branch and restore the crop to health. Alternatively, if a player has access to the Lunar Magic spellbook they may use the Cure Plant spell instead, which is substantially more expensive but may save the player valuable inventory space during a crop run. Crops grow in real-time, so they may become diseased when a player is offline. In addition, crops that have been cured of disease may become afflicted once again. Fully grown crops will not become diseased.
Crops cannot become diseased in the first growth stage (i.e. immediately after the seed has been planted).
Reducing disease risk[edit | edit source]
Each crop type has a predetermined probability of becoming diseased each crop window. Treating a farming patch with compost, supercompost or ultracompost before (or immediately after) planting a crop reduces the chance of disease during all growth cycles, rounded down to the nearest 1/128th. Compost reduces disease risk by 50%, supercompost by 80%, and ultracompost by 90%. The risk of a plant becoming diseased without any treatment varies depending on the crop (and in some cases the specific patch). These rates are unknown, except for the following crops:
|Plant||Disease Chance per Cycle||with Compost||with Supercompost||with Ultracompost|
|All Fruit trees||17/128 (~13.3%)||8/128 (~6.3%)||3/128 (~2.3%)||1/128 (~0.8%)|
|Maple Trees||12/128 (~9.4%)||6/128 (~4.7%)||2/128 (~1.6%)||1/128 (~0.8%)|
|Magic Trees||8/128 (~6.3%)||4/128 (~3.1%)||1/128 (~0.8%)||0/128 (0%)|
|All Herb||26/128 (~20.3%)||13/128 (~10.2%)||5/128 (~3.9%)||2/128 (~1.6%)|
The probability a crop will fully grow without getting diseased and dying is , where is the probability found in the above table and is the number of growth cycles the crop requires to fully grow. For example, fruit trees require 6 growth cycles, and if ultracompost is used, the tree has a chance of fully growing without becoming diseased and dying.
Magic Trees can still become diseased when using Ultracompost.
If a player forgets to treat a farming patch, the expensive but useful Fertile Soil spell may be used to treat the patch with supercompost (or ultracompost if you have previously read the Ash covered tome) both before and after planting a seed or sapling. Supercompost and ultracompost can also be used before or after.
An amulet of nature alerts a player to disease if worn, and may also be rubbed to check whether or not a plant is still healthy.
Eliminating disease risk[edit | edit source]
Watering allotment, flower, and hops patches with a watering can eliminates the risk of disease occurring at the end of that growth cycle. During the next growth cycle, the plant moves from being watered back to normal and becomes at risk for disease once more, unless it is watered again. Only allotment, flower, and hops patches may be watered.
Otherwise, the only way to eliminate disease risk entirely is to pay one of the farmers near the farming patch to watch over it and ensure that it grows to completion. Payment must be in the exact form requested. For instance, a farmer does not accept 5 apples in lieu of a basket of apples. However, farmers do accept noted payment. Note that farmers require separate payment for each allotment patch.
The belladonna, mushroom, do not have farmers available to oversee them, however. Herb patches cannot be watered, and despite farmers overlooking the allotment patch, they do not accept payment for either the flower or herb patches.
Poison ivy bushes are immune to disease. Farmers will not accept payment to watch over a poison ivy bush.
The special herb patches unlocked by completing My Arm's Big Adventure and Making Friends with My Arm are immune to disease, although herb yields may still be increased by treating the patches with super/ultracompost.
References[edit | edit source]
- Jagex. Mod Kieren's Twitter account. 7 September 2017. Mod Kieren: "So with the release of Ultracompost I figured I'd explain how compost affects crops dying. Sorry it is very word heavy! Fire any questions:)." NOTE: The image in the tweet says the ultracompost multiplier is 1/7, but later in the thread it is corrected to 1/10. Additionally, the image says "Fruit Trees have 4 chances of becoming diseased" but it's actually five, as can be seen in Apple tree seed for example. Therefore his statement that "fruit trees have a 96.9% chance of surviving" if using ultracompost is incorrect -- it is actually 96.15%.