Reefer trailer ant infestation

Greetings Drivers.......interesting problem for ya, company purchased used refrigerated trailer, while at pickup, discovered by shipper.....ants.....trailer rejected. later discovered trailer appears to have become nesting place in parts of trailer.
Tried some treatments my self (-20 over night, insecticide, trailer wash, silicone holes/cracks), yet ants have retreated in walls .....perhaps behind insulation, and of course walls between behind refer engine.
reason i suspect continued infestation, i found a trail inside refer motor compartment after trying to treat trailer my self.
obvious problem is trailer rejection with some shippers.......
not sure how effective household exterminator can be, most won't treat trailer
share your solutions if you've had this problem and how you solved it........................
thank you ........"be safe"

 

Thatz agreeable, bro, i thought of that, i suspect there ain't a quick solution, but i needed your experience to help confirm this, thank you....."be safe, fortycalglock"

 

yes sir, yeah, agreed, i work for small co.. no trailer swaps available, so we were looking for quick solutions......but it appears as you said it's a unique problem that sucks......and it's gonna take some time and alternative freight, which i discussed with dispatcher........appreciate ya, ur experience is always welcomed, "fortycalglock".........."be safe"

 

I'm in temple, ga.......yes! i thought about fumigation....but i ruled it out due to suspected costs. it's a small co., but ima investigate, location, pricing in this area......cuz i have no idea of extent of infestation and may end as only solution..........good advice "Wichris" appreciate ya, ur experience is welcomed........

 

Thankz "#1Kenworth"........makes sense.......u got me thinking if i use combined approaches, except i'm not finding any fumigation services in this area, as "wichris" suggested......i got a local exterminator coming out tomorrow, he says if he can't treat effectively, no charge, and advise......i appreciate your experience "#1 Kenworth"...........always welcomed