I am afraid my speakers, probably made of sandwich wood, are infected with wood warms or termites. Is it safe to fumigate them without taking them apart. Is there a safer effective other way. Thanks.
Were did you get those speakers, from the jungles of Africa? Seriously, I would be concerned about the fumigating chemicals depositing on the drivers, crossover and wires which might have a long-term deleterious affect.
Why do you think you have wood warms?
If you fumigate with Vikane, you are probably OK. But check with the fumigators.
If you think you've wood boring insects, get the speakers out of your house before the rest of your furniture gets infected! If they are in your speakers, they may be elsewhere in your home. How long have the speakers been in your home?
First, back passive radiator's screw holes have thin wood dust in them. Strangly enough, those are the only spots I see traces of warms. Speakers are painted in black satin laquor.
Is there any way to deal with warms ather than fumigation?
1. Remove drivers and crossover.
2. Take all the precise measurements of a speaker cabinette inside and out
3. Burn the speaker cabinettes either in fireplace(save an electricity) or do some BBQ over the charcoals.
4. Take the measurements to the carpenter and re-create speaker cabinettes.
5. Place back drivers and crossover.
One way to see if you have something exotic in them is to seal then in a heavy-duty plastic bag. Leave it be for a while and then see what kind of dust might be getting thrown out by their activity. Also, sealing them in plastic will prevent further invasion to your home.

I would question your assumptions that there is something living in there. If you do seal them in plastic wrap some tissue paper around them at the base as whatever is coming out will be easier to see.

I would consult an expert keeping in mind that most pest control inspectors are only familiar with local bugs.
Here is an idea:
Open speakers, drop one moth ball into each. Should kill any warms and each ball will disappear in a week or so.
The last time I had warms in my speakers, I replaced the soft dome tweeters with aluminum ones.
Sometimes, especially with heavy speakers, the woodworking dust is not entirely removed after production. Even with some good cleaning, fine wood dust can settle over time. Your speakers might be OK. But, to be safe, you may wish to call an expert to examine them. Unclejeff and others also have good suggestions.