--- a/net/minecraft/world/level/block/BlockWitherRose.java
+++ b/net/minecraft/world/level/block/BlockWitherRose.java
@@ -66,7 +66,7 @@
         if (world instanceof WorldServer worldserver) {
             if (world.getDifficulty() != EnumDifficulty.PEACEFUL && entity instanceof EntityLiving entityliving) {
                 if (!entityliving.isInvulnerableTo(worldserver, world.damageSources().wither())) {
-                    entityliving.addEffect(new MobEffect(MobEffects.WITHER, 40));
+                    entityliving.addEffect(new MobEffect(MobEffects.WITHER, 40), org.bukkit.event.entity.EntityPotionEffectEvent.Cause.WITHER_ROSE); // CraftBukkit
                 }
             }
         }