Proofing and exclusion work is essential to ensure that you don’t simply remove one colony of rodents ready for the next to move right in! Mice can squeeze through a hole the size of your little finger (or a US dime) and rats through a hole the size of your thumb (a US quarter)… finding these points of entry is much easier in a clean environment, so make sure you have a good tidy up first. Some points of ingress will be obvious, especially around doors and windows, but pay special attention to parts of the building where joists, pipes and cables enter and leave; any holes made to accommodate these are easy access for rodents. And don’t forget sewers, even small pipes are a rodent super-highway.
Proofing and exclusion work may be costly and require frequent maintenance, but good housekeeping and building upkeep should be everyone’s priority as a lack of such is precisely what invites pests – it is far easier to prevent an infestation than eradicate one.
How much rat bait is enough?
Under-baiting is a common mistake that can lead to a false conclusion that the rats are bait shy or even resistant. So here are PelGar’s simple guidelines to follow:
Low infestation - rodents only seen or heard at night and only small, but significant, damage by gnawing. Few droppings evident and only a few active burrows:
High infestation - rodents often seen in the daytime, conspicuous damage to property and goods by gnawing. Abundant droppings, runways evident and many active burrows:/p>
Tackle large populations by increasing the number of bait points, not the amount of bait within them. This helps get bait to more rodents quickly and efficiently but it is not simply a case of over baiting to achieve quick results, as this will adversely impact non-targets and the environment - and be a wasted cost for you and the customer.
Keep on top of your inspections to record the amount of bait put down, so you can follow the patterns of activity to assess what’s going on at the site. Be aware that it can take some time to overcome the neophobia with rats. Keep baiting until all feeding activity has stopped.
If bait take is still low after a couple of weeks but recent activity is evident then it’s time to relocate the bait stations to an area of higher activity and check that your proofing work is driving rodents towards the bait.
If you find that bait take is substantial over a long period consider whether non-target animals are consuming the bait or an immigrant population has moved in. Check through your proofing and exclusion work to resolve these issues. Only if neither of these are occurring can resistance be suspected.