Rodenticides are a specialised form of pesticide designed to control rodent populations, typically formulated as baits aimed at killing rodents such as rats, mice, and squirrels. The choice of active compounds in rodenticides is critical in determining their effectiveness, addressing factors like time to effect, resistance management, and safety concerns, including potential impacts on non-target species and the environment.
The most commonly used active compounds in rodenticides include bromadiolone, difenacoum, brodifacoum and difethialone. Selecting the appropriate compound is essential for effectively targeting specific rodent types while also considering safety and environmental concerns. This blog will cover the unique properties of each compound, offering guidance for safe and effective use.
Rodenticide formats and their applications
Rodenticides are available in several bait formats, each suited to specific environmental conditions and pest control strategies. Understanding these formats helps in selecting the best option for the situation. Below are some common types of bait formulations:
Blocks
Blocks are designed to withstand various weather conditions, making them suitable for outdoor use in areas with high moisture levels. Their solid structure minimises the chance of spillage, providing a longer-lasting option for ongoing rodent control. Blocks have an added benefit, rodents will use them as a gnawing aid, ingesting small amounts as they do so. Blocks can also be skewered inside a bait station via fixing bar/ nail to prevent the bait from being moved.
Drawback: Due to their hardness, blocks may be less appealing to rodents if softer, fresher food sources are available nearby. They are best used in locations where alternative food sources are limited.
Whole Grains
Also known as loose bait, grain baits are typically infused with active compounds and made from natural grains such as oats or wheat, making them highly attractive to rodents. This format is particularly effective in environments with competing food sources.
Drawback: Grain baits lack weather resistance and when secured in a bait station should be placed somewhere to prevent exposure to moisture. Whole grains tend not to be as effective for mice as they are with rats, as mice can remove the husk and consume the seed without being poisoned. Being smaller, they are also accessible to non-target species, so they must be in a secure containment for the safety of other animals.
Pellets
Pellet bait is compact and dense, making it easy for rodents to carry back to their nests. Its small size allows rodents to consume the lethal dose more quickly, enhancing the bait’s effectiveness when rapid control is needed.
Drawback: Pellets can be easily scattered and picked up by non-target species, so they must be placed carefully and used in a secured bait station to prevent accidental ingestion by pets or wildlife. Pellets also tend to break down if left in wet weather.
Pasta
Also referred to as soft bait, this type resembles a paste made with oils and flavourings that are particularly attractive to rodents. The blend of ingredients includes wheat flour and grains that are often found in pasta, giving it its name. Its soft texture makes it highly palatable and easy to place in bait stations. Soft baits are ideal for use around restaurants or food storage areas, as they compete effectively with other food sources.
Drawback: Soft baits are highly attractive and may also attract non-target animals. They should be secured within bait stations. Additionally, they have a shorter shelf life and require more frequent replacement.
Rodenticide colours: purpose and benefits
Rodenticide baits are commonly manufactured in bright, unnatural colours, such as vivid blues, greens or pinks. These colours serve multiple purposes:
- Deterrent for Non-Target Species: The unnatural colours help prevent accidental ingestion by pets and birds, which are less likely to mistake brightly coloured bait for food.
- Identification and Monitoring: Although there is no standardised colour coding to indicate specific active compounds, some manufacturers may use colours to differentiate baits targeted at various rodent species. Bright colours also aid pest control professionals in identifying and monitoring bait placements.
- Weather Resistance: The fade-resistant colours help the bait maintain its visibility and effectiveness even under adverse weather conditions like intense sunlight and heavy rain.
- Tracking Rodent Activity: In some cases, the colouring is visible in rodent droppings, providing a visual confirmation that the bait has been ingested. This makes it easier for pest control professionals to assess bait effectiveness.
This colour coding is integral to safe and effective pest control practices, enhancing safety and monitoring without directly indicating active compounds.
Compound Breakdown
Earlier in this post we touched upon the most popular and commonly used active compounds in rodenticides. We have broken these down in further detail here:
Bromadiolone
Bromadiolone is a highly effective rodenticide compound primarily used to target rats and mice. It is most effective when consumed multiple times, allowing the rodent to ingest a lethal dose gradually.
One popular product containing bromadiolone is the Bromag Bromadiolone 10kg sack, a whole wheat-based bait with a red/brown marker dye. This dye serves as an indicator when the bait has been consumed, aiding in monitoring.
Due to its palatability and inclusion of a taste deterrent for human safety, this compound is ideal for sites with significant rodent issues, such as agricultural areas. While initial feeding effects can be seen within a day, visible results may take several days. Bromadiolone is a professional-grade rodenticide that requires a valid rodent control certificate.
Difenacoum
Difenacoum is a multi-feed bait, meaning that rodents must feed on it several times over a few days to consume a lethal dose. This gradual approach encourages communal feeding, which in turn attracts more rodents to the bait site, making it an effective choice for managing larger populations. Manufactures of Difenacoum tend to use green/blue dyes.
Typically, difenacoum-based baits are used in and around buildings and in transport vehicles. Made from food bases such as cereal, it is highly potent and particularly effective against rodents that may have developed resistance to other poisons.
Brodifacoum
Brodifacoum is known as one of the most potent rodenticides available, and as a single-feed bait, it can deliver a lethal dose in a single feeding. Results are typically observed within 3-4 days, making it ideal for situations requiring rapid control. Manufacturers of Brodifacoum products tend to use pink/purple dyes.
Due to its high toxicity, brodifacoum should always be placed in tamper-proof bait stations, particularly in locations where pets, especially dogs, may be present. Direct consumption of poison from non-targeted species is uncommon, however with Brodifacoum being active in the blood system of the poisoned rodent, secondary poisoning from consuming the poisoned rodent can occur. Its strength makes it a good choice if rodents appear resistant to other poisons. However, extreme caution is required, and bait should be placed in inaccessible areas like under floorboards or in cupboards.
A recommended product is the Brodiag 10kg sack, suitable for indoor and perimeter use in buildings. Purchase of brodifacoum products typically requires a rodent control certificate or proof of membership in the Farm Assurance scheme.
Difethialone
Difethialone is especially effective within farm buildings experiencing significant rodent infestations. A leading product in this category is Rodilon’s 10kg whole wheat grain bait, which is noted for its high potency and palatability. Additionally, Difethialone is known for its lack of resistance issues, making it a reliable choice in settings with persistent rodent challenges. Direct consumption of poison from non-targeted species is uncommon, however with it being active in the blood system of the poisoned rodent, secondary poisoning from consuming the poisoned rodent can occur.Â
Safety and Environmental Considerations
To protect non-target species, it is essential to place rodenticide baits inside secure bait boxes. Using a reliable bait station ensures that the correct amount of bait is deployed while keeping it shielded from environmental exposure, which could otherwise reduce bait effectiveness. Additionally, secure bait placement minimises risks to non-target species and contributes to safer, more controlled pest management practices.
Conclusion
Choosing the right rodenticide compound and bait format is essential for effective rodent control. Understanding the unique properties of each active compound, whether multi-feed or single-feed, fast-acting or gradual, enables more strategic and responsible pest management.
If you need more information on our range of rodenticides, then please give us a call on 01842 765 634, and we will be happy to talk through your options.
