Haven't had any trouble, myself. Worm Food is crafted in the 5th tab (from the left). If it's definitely not showing up there, try pressing X while in the crafting menu to toggle the showing of only available items. Think For Yourself; Question Authority.
It is summoned using Worm Food from within the Corruption and Underground Corruption, or by destroying 3 Shadow Orbs that spawn in Corruption-filled worlds. It can be summoned at any time of day. Do note that Eater of Worlds shoots vile spit in Expert and Master mode.
To spawn, the World Feeder only requires the player be considered to be in a Corruption Biome. Spawn surfaces do not have to be Corruption Biome blocks.
It is summoned using Worm Food from within the Corruption and Underground Corruption, or by destroying 3 Shadow Orbs that spawn in Corruption-filled worlds. It can be summoned at any time of day. Do note that Eater of Worlds shoots vile spit in Expert and Master mode.
“A massive worm who dwells in the corruption.” The Eater of Worlds is a pre-Hardmode Corruption-themed worm boss. It can be summoned when three Shadow Orbs are destroyed in a Corruption world, or when a player uses Worm Food anywhere in the Corruption or Underground Corruption biome.
The Eater of Worlds is summoned by destroying 3 Shadow Orbs in the Underground Corruption. The player can also use the Worm Food in the Corruption. It can be summoned at any time.