Rodenticides – Confused??

Wednesday, 24 April 2013 15:15
    Going back 20 or 30 years the range of baits available may have seemed a lot simpler – so why have things changed so much and which product is supposed to be used when? The technical team from leading British manufacturer PelGar International sheds some light. The plethora of rodenticide formulations available in the market today is a sign of how rats and mice have evolved and adapted to modern life. Over the past two or three decades, widespread resistance has been seen to the first generation anticoagulants such as warfarin. This spread of resistance has resulted in the introduction of second generation rodenticides, each of which has an unique profile – see the table below.


    AnticoagulantLD50 mg ai/kg Mouse/RatBait Concentration (PPM)LD50 (g of bait) Mouse/Rat*LD50 (g of bait/kg) Dog
    Difenacoum0.8 / 1.80500.4 / 9.01000
    Bromadiolone1.75 / 1.13500.9 / 5.6200
    Brodifacoum0.40 /0.27500.2 / 1.45.0


    The figures for dogs are shown to give an indication of toxicity to non-target animals to help understand how lethal certain active ingredients can be.
    Difenacoum – Multi-feed, indoor and outdoor use by professionals and amateurs.
    Always the product of choice for mouse control and for rat control where there is concern about secondary poisoning, e.g. presence of birds of prey.
    Bromadiolone – Multi-feed, indoor and outdoor use by professionals and amateurs.
    The product of choice for general rat control. It is less than half as effective as difenacoum on mice.
    Brodifacoum – Single-feed, indoor use only, professional use only.
    Only for use indoors where other anticoagulants have failed to gain control. Up to 200 times more toxic to non-target animals than difenacoum.
    This is a general guide to the three most common anticoagulants used in the UK. It is clear to see from the lethal doses why the single-feed rodenticides, such as brodifacoum, are appealing to use, but it is also important to understand how dangerous they can be due to their high toxicity to non-targets.
    An understanding of the different actives helps us to appreciate why there are so many different products available. The following guide gives you the ins and outs of the various products available and which to use in different situations.
    WHOLE WHEAT BAIT – the staple for rat control in the country/rural environment. Rats naturally feed on cereals and as such a treated whole wheat bait is generally very effective. Whole wheat baits offer the most economical control for most rat infestations.
    CUT/CHOPPED WHEAT BAIT – designed with mouse control in mind and also effective for rat control. Mice will kibble whole grain baits, peeling off the treated outer layer and only eating the inside, they will still die but it will take considerably longer to consume a lethal dose.
    BLOCK BAIT – or more specifically wax block baits have grown in popularity over the last ten years. Though generally not as palatable as wheat baits they offer security as they can be wired or nailed in place or secured inside bait stations. Effective for both rat and mouse control block baits, due to their wax content, are ideal for use in damp conditions.
    PELLET BAIT – good for use in situations where rodents have been feeding on a compound feed. Pellet baits are less popular in the UK but are very palatable and effective on both rats and mice. For use in dry locations only, pellet bait spoils quickly in damp situations.
    PASTA / PASTE BAIT – one of the newest products to be launched in the UK paste baits offer an extremely good alternative to wheat and blocks baits. Made from flour and fat (either vegetable oil or lard) paste baits are highly palatable and can be secured in place on wires or in bait stations. Paste baits are ideal for use in situations where multiple food sources are available or where rodents have declined to take other baits.
    Tips for effective bait placement
    Once we know the best active ingredient and formulation to use there are a few good tips that can be followed for effective control.
    Rats: Identify burrows and feeding places, faeces are a good indication of where rats spend a lot of their time. Bait can be placed down burrows using a long spoon or bait sachets can be used. Bait stations should be located along the paths where rats travel and around the places where they feed. Rats are neophobic (wary of new objects etc.) and so it may take several days before they accept the bait. After 7-10 days any untouched bait points should be moved to areas of higher activity.
    Mice: Unlike rats, mice are very exploratory and inquisitive so will actively investigate new objects and food in their environment. Bait should be placed where the highest levels of activity are seen – usually where you find the most faeces and near nests. A useful tip for mouse control is actually to move bait points when they are topped up as mice will see this as something new to investigate and feed from.
    In any rodent control campaign it is important to protect bait from non-target animals, check bait points and top them up regularly. Remember to search for and remove dead rodents and waste bait, and always keep a record. For further help and advice order free copies of PelGar’s ‘Six Steps to Successful Rodent Control’ along with its detailed staff training guide. Call 01420 80744 or e-mail [email protected]

    About Us

    PelGar International was incorporated in 1995 to develop and supply innovative and novel rodenticide and insecticide products to the global public health pesticide market. PelGar believes that, while the active ingredients used in the industry are common, the target pests and the environment in which they live are very different. Providing cost effective control therefore means that the active substance needs to be available in a wide range of formulations and this is where PelGar’s expertise lies.

    Contact Information

    • Address: PelGar International Ltd, Unit 13 Newman Lane, Alton, Hampshire, GU34 2QR, UK
    • Tel: + 44 (0)1420 80744
    • Fax: + 44 (0)1420 80733
    • Email: [email protected]
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