–Wilson, when examining a Diseasing Barrent Bush or Stone Fruit Bush
“Feeling okay, friend?”
–Wormwood, when examining a Diseasing Barrent Bush or Stone Fruit Bush
“I think it's coming down with something.”
–Winona, when examining a Diseasing Barrent Bush or Stone Fruit Bush
“Something wrong with it...”
–Wurt, when examining a Diseasing Barrent Bush or Stone Fruit Bush
Disease was a feature that affected replanted Plants in Don't Starve Together, introduced in A New Reign and removed in Reap What You Sow. Diseased plants had the appearance of being surrounded by flies and became darker in color before dying and disappearing. They did not drop their specific resources, but instead yielded Rot if picked or dug up by the player with a Shovel.
After a plant had been replanted by the player, it had a timer set to 50 days. Once that timer was up, it had a 10% chance to become diseased. If the chance failed, the timer was reset to another value between 30-70 days and the process would repeat itself. If it was successful, the player's character would comment when harvesting the plants for 4-6 days to warn the player that the plant would become diseased. If it turned fully diseased, the plant's disease would begin to spread to other nearby replanted crops every 1.5-2.5 days without warning. The player could dig up the plant in its warning phase in order to manually reset the timer (or at the very least if the plant was already diseased, the player could dig it up to prevent the disease from spreading, but the diseased plant was destroyed in the process).
The following table illustrates the variants available for each type of resource, note that the sources on bold were invulnerable to Disease:
Disease was added to the game far before A New Reign was announced, becoming part of the latter update after the Beta release with some tweaks. Before that, Grass Gekkos and Twiggy Trees were also able to become diseased.
There are unused sprites for Diseased Logs, Juicy Berries and the dug version of each plant in the game's files.
Disease was an unavoidable mechanic and there was no way to fight against it, but there were some strategies how to "counter" to it.
The basic resources such as saplings and grass tufts can be replaced by spiky bush/Twiggy Tree and grass gekko.
Wickerbottom is a very efficient character when it comes about farming resources, using her book: Applied Horticulture. It can instantly Ripen saplings, grass tufts, berry bush etc. making disease less of a scary threat.
If the Bee Queen or Klaus has been killed for the Bundling Wrap blueprint and a couple of Meatbulbs, Wickerbottom can go to the Ruins where they find Cave Lichen. Place the Meatbulbs onto the lichen area and wait for eyeplant to spawn, repeatedly reading applied horticulture then killing the Meatbulb will grant a huge amount of Lichen. Make sure that you don't take your time doing this strategy and bundle them fast, as they spoil very quickly when digested by the Meatbulb.
Bull Kelp which are not affected by disease and don't need to be fertilized, but are not renewable make up a great vegetable/filler food source.
Stone Fruit Bush can possibly be a superior choice against Berry Bush, since Sprouting Stone Fruit can be mass farmed as Wickerbottom using Applied Horticulture which come from Stone Fruit and do not disease nor need to be fertilized at all.
Spending a bit of time at the Desert to collect Tumbleweed is a great way to get grass and twigs. Making a base there is also beneficial.