Black tips, spots and nibbles on succulents

[Aussie gardener]

Hi all! A few weeks ago my succulents started getting black tips and spots. It spread from pot to pot. I'm attaching pics of several, they are all at different stages.
I sprayed them with liquid Copper (followimg a recommendation I found online) but they are now worse, with some even having been 'nibbled'.
I'm afraid this will spread to the healthy ones even though I'm keeping them apart.
What caused this, how do I stop it and how do I prevent it in future? Also what do I do with the diseased ones?
I grow these to sell, gift and also I keep some so I'm devastated that I lost more than half my crop. Please help!

 

[oneeye]

The reason for brown leaves on succulents is sunburn or sun damage. They can't be moved to a sunny bright location, or hot spot with higher temps too fast. I would keep the chemicals off them too, because the succulents don't like it. SUNBURN

 

[cpp gardener]

I think you also have some kind of insect or mollusk problem as well. Your second picture has damage that looks like a small snail or slug has been nibbling. The 4th picture looks perfectly healthy and undamaged. I would check very carefully underneath the pots and lowest leaves for slugs/snails and insects. Something has been chewing and you need to look very carefully for the little monsters.

 

[oneeye]

Wow, I see what you are talking about cpp, I didn't see that at all, looks like some kind of pest damage. Aussie get a magnifier and look at the plants closely and get a good look to see what you have for sure. The brown tips are from sunburn.

 

[angiegurll1o1]

unfortunately I cannot say definitively what the problem is, but i think a solution might be to repot them. taking them out will give you the opportunity to take a closer look at them to inspect for bugs, fungal infections, etc. and see if they'll get better in fresh soil. i would also spray the crap out of them with an organic treatment using something like neem oil or hydrogen peroxide.