First, you need to determine why you're getting ants and TERMITES. Once you have that answer, you can start to mitigate the cirumstances.
BOTH insects need certain 'conditions' to thrive. Ants, for example, need a food source and fairly dry conditions to nest. IF they're feeding on your food, or your crumbs, or dead termites, get rid of the food source and they'll have to go elsewhere (or die). At the same time, if for the sake of arguement, the house is very clean, heavy rain or temporarily soggy conditions outside will force the ants to the surface. (They aren't born with scuba gear.) If this is the case, the problem should be temporary. You should assess the landscaping around the foundation. Are your gutters leaking or overflowing when it rains? Are your downspouts 'dumping' water near your foundation? Does the landscaping around the foundation have a NEGATIVE slope (towards the house)? Do you have a trees/flowers/vegetation 'right up against' the house? Do you have a large amount of shade? (Hang on - I'll return to answers in a moment.)
Now, as for termites, they 'operate' in a similiar way as ants. In this case too, you need to become a termite to understand how to get rid of them. These guys need darkness, dampness, a food source, and a relative constant temperature to survive. (About answers to this and the questions I asked a moment ago.) If you want to get rid of the insects, you need to ALTER THE CONDITIONS IN WHICH THEY THRIVE. With ants, get rid of the food source. Fix your leaking/sagging gutters. Route the water from the downspouts AWAY from the foundation. Re-landscape around the foundation so it's sloping AWAY from the house. Remove / Prune any vegetation that's within 2' of the foundation so you can improve air flow which will dry out the soil and allow some sun in. Remove / Prune your trees and bushes AWAY from the house to allow sun and air in.
Yes, this is a lot of work. If you have termites, you have BIGGER problems than you might think! The landlord is 'losing' a source of income, literally! In the next steady/heavy rain, put on some boots and get an umbrella and walk around the house. Look at the gutters and downspouts and roof-line and landscaping around the foundation for symptoms that are allowing water to pool or get into the house. IF your crawlspace is dirt, buy some 6 mil thick plastic and cover the ground. Overlap it 6" and lay some bricks, or something sporatically around the outer edges (to keep it down.) You can lay a few here and there in the 'middle area' too, if you want. Sure, you can spray or bug-bomb but that's only temporary (as you already seen from the steps you've taken already.) Again, in short, you need to ALTER THE CONDITIONS IN WHICH THEY THRIVE. IF you know where the ants and termites are coming in, you can try the Ant Hotels for the type of ant you have. They've worked pretty good for me when we get lasting, steady, rain over 4, 5, or more days. (ALL the bugs get 'ansy' when there's too much water.) If you ants are, like 1/8", give or take, they're probably Sugar Ants. If they're 1/4", give or take, they may be Black or Red ants. Yet, they could be Carpenter Ants (which do a lot of damage similiar to Termites.)
In addition to all the 'outside' work I listed, you might want to convince the landlord that IN THE MEANTIME, he ought to have a Pest Control COmpany do some 'temporary' mitigating work. While that's taking place, do the outside survey and report back to the landlord. If you can do some of the work, like trimming or removing vegetation, offer to do so. (Fixing gutters and re-landscaping may be a 'liability' on his insurance.) Just convince him that you and he can make this a win-win.
Here are a few references for you to peruse to help 'arm' you with information. Remember, ALTER THE CONDITIONS IN WHICH THEY THRIVE and you'll see dramatic results! My best to ya and hope this helps.