Block and soft bait rodenticides may be the mainstay of rodent control programs, but rodenticide pellets also have a role to play.

While block and bait rodenticides have long been a dependable mainstay of rodent management and control, pellets can still be an important tool in your arsenal, but do you know why?

Pellet and grain formulations are much less common in modern pest management; blocks and soft baits are securable and efficacious and when used responsibly, they’re less likely to be translocated by rodents, end up somewhere they shouldn’t, and pose no risk of spillage.

So why then would you bother with pellets at all? Well in many cases you shouldn’t, but there are exceptions, and the most common one is for burrow baiting.

A typical series of rat burrows

Whilst burrowing is most commonly associated with Norway rats, all three of the commensal rodent species in Australia burrow readily. Mouse burrows are most likely to be encountered in paddocks and are rarely of any interest to the urban pest manager, but rat burrows are common, particularly around agricultural and industrial buildings. One of the most effective ways of controlling a rat population is by baiting their burrows and pellets are perfect for this as they’re not overwhelming to the rats.

Samuel Wood, Asia Pacific business manager for Bell Laboratories, says that whilst many block baits are approved for burrow baiting on their label, they’re less than ideal for the job. “To the rats, the block is just a foreign object that shouldn’t be in their burrow, and they’re likely to remove uneaten or partially eaten blocks, potentially making them accessible to pets, livestock, or wild non-target species.

“Using pellets such as Bell’s Ditrac pellets can do more than just control the rats in the burrows. If paired with Ditrac Blox in perimeter bait stations, it encourages feeding from the stations, as the rats will seek out the food source they’re familiar with. And as most professional pest managers will know, once one rat has entered a bait station, it’s likely others will follow.”

Ditrac rodenticide, a compressed pellet bait

Made from the same ingredients as Bell’s Ditrac Blox, the pellets include the active ingredient brodifacoum, which is evenly distributed to ensure ingestion once rodents start to feed. “And the precise formulation of human-food grade inert ingredients ensures both bait forms are attractive and palatable to rats and mice in most situations,” added Mr Wood.

With rodents more prevalent in colder weather, now is a good time for a refresher on some of the do’s and don’ts to effectively burrow bait for rats.

Do use a pellet formulation, and a long-handled baiting spoon (or an extended funnel) to apply the bait as far into the burrows as possible. Don’t back fill the burrows with soil; this will just cause the rats to panic and re-excavate, potentially spreading bait and leaving it exposed for non-target species in the process. Gently block the burrowentrances with newspaper, to help to ascertain the level of activity. Rats will happily drag newspaper into their burrows for use as nesting material – if this happens, then you’ll know there’s still activity!

Using an extended funnel allows pellet bait to penetrate deeper into rat burrows

Do follow up. Be comfortable charging your clients for more than one visit. Visits 7-10 days apart should be effective for most infestations. And do repeat bait application to re-opened burrows. Once the burrows stay blocked, you know you’ve achieved elimination of the colony.