Help please. I found a 3 caterpillars on my grafted cacti, my 3 plants are in trouble. It could also be sunburn Im unsure how to save them. Any help or direction would be amazing

[Shmee]

Hi about 2/3 weeks ago my grafted peyote were thriving (grafted Nov last year),

The first picture was taken late Nov, I don't know if it is because there is more caterpillars' inside or it is fungus.

I will leave overnight and will probably wash the soil off and repot with new soil mix off the ( 1 peruvianus and 2 pachanoi bases). I have many other non grafted ones and they seem to not have suffered in any way. About 20 that were on the same window they have always been and some new ones recently done too. I'm confused as what could cause this. The guess I have is sunburn or light problem / Infested with something is the other. i have Williamsii, Ariocarpus and Williamsii Var. Caespitosa I have had deaths before but have been learning for a while now. I found contradictory information a lot, and have learnt the best people to learn from are people how actually do it or at least try. I have 1 window in the right spot or id have them on every possible place i have never grown bored of watching them, many mistakes over the years, the mistakes hurt but I'm happy i keep trying as they make me happy. I have grown cacti numerous other plants of all sorts for most of my life. Now stuck in 2 room appartment for a while, ill have my garden back soon one way or the other :D

I appreciate any and all help I did have a look through to see if anyone had the same problem or similar but didn't see anything.

Again thank you all for you time

Edited January 12, 2023 by Shmee

[Humboldt]

Hey Shmee, what's the turgor like? Have the grafts become soft?.  I've found with my grafts that although they take, it can be some time before they have the vascular network to deal with stressors like too much sun.