Sort:  

I use neem with an orange tree to free it of the ants. Look, for the ants you need to know where is the nest, so you can spray the entrance too.

It takes time, but it worked for me.

Again, cannabis is vastly different from fruits and vegetables and neem is not a safe option. Look up "Cannabinoid Hyperemesis Syndrome," and you'll find 90% of the cases are actually azadirachtin poisoning (aza is found in neem oil).