1. Are these spider mites?
2. Is this a mite web?
3. If so, should I assume that all of my trees have them since they’re all in the same area?
4. What’s the best insecticide for bonsai?

Hey West sai,
Yes, looks like an egg sac. My experience with mites are already beyond chemicals due to some sensitive animals on my household. I prefer to use predatory mites for the job, like in that case Phytoseiulus persimilis. Those voracious little buggers just killing and eating until no bad guy left behind, then dying out really quickly without food.

I would say no, they look like blackfly to me. Spidr Mites are tiny almost invisible to the eye, not this size

m5eaygeoff wrote: Spidr Mites are tiny almost invisible to the eye, not this size

yes, but if you shake the plant, you surely can see them!

OP, for the clear identification please count the legs, or try to make a macro photo from them. Spider mites have some ssp, so that probably we won’t know for sure, but at least chim out against what you fight.

I agree with the above comment. It is very important to be familiar with the type of pest we have to deal. To remove the confusion, it would be better to consult an expert having knowledge about this pests stuff. Choosing the firms like pest control Rocklin would be best as they would also help you to clear the infestation without harming your plants. Best luck!

This is a different picture to the first. That is a very bad case of Spider Mite,

KristiNolan wrote: I agree with the above comment. It is very important to be familiar with the type of pest we have to deal. To remove the confusion, it would be better to consult an expert having knowledge about this pests stuff. Choosing the firms like BLA BLA BLA SPAM would be best as they would also help you to clear the infestation without harming your plants. Best luck!

Spam, reported...