Divine Ire + Arakaali's Fang?

I read that this combo is great to spawn spiders but it just kills the worms and ZERO spiders spawn.

I can manually hit the worms with my dagger and boom, spiders. But divine ire channel kills them and then nothing. Why? What am I missing?

I am actually surprised you can get Spiders with hits from the weapon. Raise Spider states:

Raise two spectral spiders from each nearby corpse that will attack your enemies with Viper Strike. Each raised spider grants you increased Attack Speed and increased Damage with Poison. Enemies will not engage the spiders directly, and they are immune to damage.

And I remember Worms are destroyed on kill, leaving no corpses to raise spiders from

It doesnt work that way as Maxtrux pointed out.

You still have to desecrate and have a few corpses around to spawn spiders.
Since the spiders are immortal but are also on a timer they can always just disappear while mapping and that can be a little annoying.

You can get around this issue to some degree by using the Speakers Wreath helmet while making sure your spiders dont deal any fire dmg and thus cant ignite.
Meaning all enemies will die to the spiders poison and this counts as a playerkill which will not only trigger Raise Spider (if corpses are around) but also trigger life recovery or onslaught or endu/frenzy charges on kill and stuff like that.