I only know from my med device experience but what we do is:
1) Monthly log of a direct employee inspects the grounds for signs of infestation
2) Every 3 months an outside firm expert in pest controls visits and also inspects and treats areas. We document that agreement and the visits.
I would do that and as far as controlling the insects etc, work with the pest control company to determine the most considerate options for pests. The FDA states the method must be "EFFECTIVE." What this means to me is when an FDA auditor arrives unexpectedly there cant be evidence of insects or infestations. However you manage to do it CANNOT affect the food or product and cannot result in evidence bugs were ever there. The last part is my own perception of FDA auditors. FDA auditors expect workplaces to look clean, maintained, and have enough space to prevent mix-ups.
One clean room I audited had active fly traps in the room. Yes, you read that right. They made platinum-iridium leads that would be implanted in veterans!
An exterminator would know methods better.
TITLE 21--FOOD AND DRUGS
CHAPTER I--FOOD AND DRUG ADMINISTRATION
(d)
Pest control. (1) You must not allow animals or pests in any area of your physical plant. Guard or guide dogs are allowed in some areas of your physical plant if the presence of the dogs will not result in contamination of components, dietary supplements, or contact surfaces;
(2) You must take effective measures to exclude pests from the physical plant and to protect against contamination of components, dietary supplements, and contact surfaces on the premises by pests; and
(3) You must not use insecticides, fumigants, fungicides, or rodenticides, unless you take precautions to protect against the contamination of components, dietary supplements, or contact surfaces.