My dear four ribbed bridge has been infested with worms, so sad.

after i cut it:



Wound once cleaned out:



First i thought it was rot so i choose to cut it to save it. It was weird cause it didn't spread as usual and when i inspected the wound i found some worms. In fact there was no rot and they were slowly eating my baby from inside.
Here 2 of them (the bigger ~6mm) :


There were severals of them, from 1mm (hard to see) to 10mm, white translucent, able to move quite fast crawling and also curling on themself and spring at 1 or 2cm.

I hope it's only an isolated case. I checked the cactus crowd in the garden and it doesn't seem to spread but any information would be welcomed from you, cactus lovers.

That's a Pitty. Those Worms.... Mescal myth. Extract those bastards, maybe they re full of goodies.

Try to scrape off any visible eggs. Look at the cactus for holes in the body and poke the worm in them dead. Change soil spray the cactus with ~50% isoprop or ethanol.
Make sure to wash the alcohol off or your cactus will get chemical burns.
You could also look into getting a more "industrial grade" insect killer. Just make sure you use something that doesnt kill the cactus with it.
Also it would be best to use something that is harmless to usefull insects and animals.

I wonder if BT spray would get rid of these? It is a pathogen that kills caterpillars. I use it on my kale and broccoli. Non toxic to humans.

A decoction of nicotiana rustica or similar nicotiana app will put these little wretches in their place.
An easy and valuable plant to grow and have around.
USE WITH CARE, remembering nicotine is toxic.

It might be interesting to see what these insect larvae grow up to be. Then there would be a bigger picture to see.

I still don't know what is it (and i won't let them grow up, even for science sake !) and i had few other case (3 or 4 on few hundred of cacti so no panic yet).
When i find them, i just clean the wound, put some cinnamon and let it dry.