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Effective, systematic pest control against rats and mice

Rats and mice pose a serious hygiene problem, and wherever they appear, there is a risk of contamination and even the spread of disease.
 

Rats and mice are a serious hygiene problem

Rats can transmit up to 120 infectious diseases, which they spread via fleas, faeces, urine or bites. The best-known diseases include

  • the hantavirus (high fever, kidney failure)
  • cholera or
  • typhoid fever.

Decisive for the prevention or control of harmful rodents is appropriate farm hygiene, namely

  • Thorough barn cleaning several times a year, depending on infestation and occurrence.
  • Identify and eliminate possible entry points.
  • Consistently protect, remove and make inaccessible possible sources of food and feed that may attract rodents.

Weak points on house and yard

1 Silo
2 Grain store
3 Stables
4 Tool shed
5 Compost heap as food source
6 Firewood pile
7 Ground cover / heavy vegetation on the house

8 Missing eaves grille
9 Downpipes as a means of access
10 Clutter corner
11 Patio door
12 Sewer and its ending in the house
13 Cellar door

14 Ventilation holes in the masonry
15 Cellar window
16 Yellow sack / bio or waste bins
17 Fallen fruit
18 Birdhouses
19 Garden ponds / fish food


Planning and control in case of rodent infestation

Prebaiting

  1. First determine the rodent species (rats and/or mice) and the extent of the infestation. To do this, check possible paths along walls, identify feeding marks and possible damage.
  2. In case of infestation by only single mice indoors, traps are the more appropriate control measure.
  3. after recognising a possible route of the rodents, mark it and close off possible entrances to food sources. 4.
  4. carry out a pre-baiting along the routes by filling bait boxes with bait without active ingredient (e.g. cereal bait).
  5. Check which bait boxes have been accepted and how severe the infestation is. Move bait boxes that have not been accepted so that an optimal distribution of bait boxes along the walkways can be achieved.

Pest Control Phase

It has been shown that rat and mice control is a year-round issue with a focus from August to March. For optimal control results, divide your yard/facility into the following areas:

  • Outer barrier belt (green bait points)
  • Inner barrier belt (grey bait points)
  • Acute control area (red bait points)

The following schematic site plan should help you to adapt this concept to your circumstances.


Common causes of control failures

  • the bait is no longer fresh enough and therefore no longer attractive
  • the baits were not applied with gloves and therefore have a "human smell"
  • there are too many alternative feed options, especially those containing vitamin K, which neutralise the effect of the active substances (e.g. soy meal, cabbage leaves)
  • the bait stations were moved again and again or the rodents were disturbed in other ways
  • too few bait points were set up
  • not enough bait was added or not over a sufficiently long period of time
  • from the surrounding area, new rats keep migrating to

Follow-up control

To avoid a new infestation after successful control, the following measures must be taken:

  1. Removal of possible food sources (food, rubbish, etc.).
  2. Removal of rubbish and waste that could serve as shelter.
  3. If possible, make accesses to the interior (crevices, holes, cat flaps, drains, etc.) inaccessible to rodents.

Documentation

Documentation is important for systematic control and its success. In addition, various laws and regulations in agriculture require appropriate measures to ensure a standard of hygiene. This also includes the control of rodents and their documentation.

  1. Create a site plan and draw the bait sites in the individual zones.
  2. Mark the bait points with continuous numbering and make a list of what was baited, when and how often.

Correctly identify rodents

Norway rat (Rattus norvegicus)

Norway rat (Rattus norvegicus)
Life span:1 – 2 years
Head/torso length:19 – 29 cm
Live weight sexually mature:240 – 520 g
Birth rate / year:4 – 6
Offspring / birth rate:6 – 8
Characteristics:
  • large, powerfully built
  • angular skull
  • blunt muzzle
  • thick tail (shorter than head/torso length)
  • small, close-fitting ears
Essence:
  • very suspicious of new things and new food
  • prefer familiar and constant environments
Activity:
  • crepuscular and nocturnal
  • mainly along familiar paths
  • live mostly on the ground
Food intake:
  • usually feed in two to three familiar places per night (20 - 30 g)
  • need water separately

House rat (Rattus rattus)

 House rat (Rattus rattus)
Life span:1 - 2 years
Head/torso length:16 – 24 cm
Live weight sexually mature:200 – 400 g
Birth rate / year:6 – 10
Offspring / birth rate:8 – 12

 

Characteristics:
  • pointed snout
  • eyes and ears relatively larger than in the Norway rat 
  • brown/grey with grey underside
Essence:
  • live socially in family groups with a fixed social structure
Activity:
  • diurnal and nocturnal
  • can jump and climb well
  • largely avoid water
Food intake:
  • prefer plant-based food (grains, fruits, seeds, roots)
  • they often do not touch food they do not know

House mouse (Mus musculus)

House mouse (Mus musculus)
Life span:0,5 – 1 year
Head/torso length:7 – 11 cm
Live weight sexually mature:20 – 25 g
Birth rate / year:6 – 8
Offspring / birth rate:5 – 6
Characteristics:
  • small
  • petite build
  • pointed muzzle
  • large, slightly hairy ears
  • tail length = head/torso length
Essence:
  • very curious
  • do not avoid new things or new food, but investigate them
Activity:
  • predominantly nocturnal
  • very good climbers
  • live mostly on the ground
Food intake:
  • feed in approx. 20 places per night (2 - 3 g)
  • can utilise the water content in the food

Vole (Arvicolinae)

Vole (Arvicolinae)
Life span:1 – 2 years
Head/torso length:8 – 22 cm
Live weight sexually mature:60 – 150 g
Birth rate / year:3 – 4
Offspring / birth rate:approx. 4 - 6
Characteristics:
  • blunt head
  • small ears
  • very soft fur
  • mostly grey, but also sand-coloured or dark brown
  • Belly always lighter in colour than the rest of the coat
Essence:
  • very curious
  • are not afraid of people
Activity:
  • active at dusk
  • eagerly digging and burrowing, not only in the garden, but partly also on lawns
Food intake:Fruit, grass, roots, herbs, sprouts, mushrooms, acorns, insects, worms

Pest control products from Kerbl

cit Logo

In addition to farm hygiene, Kerbl products help to control hygiene pests in acute infestations.

Under the traditional cit brand, Kerbl offers proven, comprehensive and inexpensive rodenticides with different concentrations of active ingredients and formulations.


 Grain baitBait blockPaste bait (gel pads)
Ambient conditionDry area, little/no possibility of other food sourcesDamp environment (sewerage system), also in the presence of other food sourcesAny environment, even in the presence of other food sources
CharacteristicEasy to handle, good acceptance when freshSupports nibbling behaviour, easy to handle, good acceptance over a longer period of time, suitable for monitoring (monitoring the infestation)Easy to handle, very attractive for rats, as liquid is also absorbed liquid is absorbed via food
Rat baitingevery 5 metres: 90 - 100 gevery 5 metres: 5 - 10 blocks (20 g) or 2 blocks (100 g)every 5 metres: 7 - 14 sachets (15 g)
Mouse baitingevery 2 metres: 20 - 30 gevery 2 metres: 1 - 2 blocks (20 g)every 2 metres: 2 - 4 bags

This information is a rough recommendation. The exact dosage can be found in the product instructions for use.


Effective chemical rat and mouse control with cit products

Our cit products for chemical rat and mouse control offer effective solutions in three product categories with different active ingredients. The baits consist of cereal grains, oat flakes or pastes, depending on requirements, to control rats and mice efficiently. The BrodiPads and BromaCereal variants are ideal for hard-to-reach places and damp environments. RatStop DF blocks offer weatherproof alternatives for indoor and outdoor use. All products are highly attractive and reliable.

Difethialone, Brodifacoum, Difenacoum and Bromadiolone are the best-known active ingredients and have been used successfully for years in households, communities and agriculture to control rats and mice.


Example calculation for the amount of rat bait with 50 ppm active ingredient content

Baits with less than 30 ppm active ingredient content must be absorbed approx. 30 - 40 % more to be effective in the same time. This does not apply to the Bayer products Brumolin and Rodilon with the active ingredient difethialone. The active ingredient in combination with the special formulations work like conventional high-dose products.

Lethal dose of rodenticide/animalBrodifacoumBromadiolonDifenacoum
Mouse 25 g0,2 g0,875 g0,4 g
Rat 250 g1,35 g5,65 g9,0 g
cit BromaCereal 25
cit BrodiPads 40
cit RatStop DF Block 25
cit RatStop DF Cereal 25

Paste baits are popular because on the one hand they are easy to apply and on the other hand they are very attractive to rodents, despite possible other food sources.

cit BrodiPads 40
cit RatStop DF Cereal 50

Pest control from Envu

Kerbl and Envu work closely together in the field of professional rat and mouse control. As an exclusive partner, Kerbl offers both the well-established Brumolin forte rodenticides and the innovative products under the Harmonix brand for professional users: Rodent Paste and Monitoring Foam.

Our Envu products offer highly effective solutions for chemical rodent control. Harmonix® Rodent Paste uses vitamin D3 for optimal resistance management. Brumolin® Forte and Rodilon® Paste are proven baits containing the bittering agent Bitrex® to prevent accidental ingestion. Racumin® foam guarantees ingestion through fur contact and is ideal for hard-to-reach areas. All products are suitable for indoor and outdoor use and offer reliable protection against rats and mice.

Brumolin® Forte
Paste Rodilon®
Schaum Racumin®
Harmonix® Rodent Paste

Under the Harmonix® brand, Bayer has developed innovative products for the effective control of rodent pests. These focus on resistance management, the targeted use of rodenticides and safe pest control.

Harmonix® Rodent Paste

The product innovation in the chemical segment of mouse and rat control! The active ingredient cholecalciferol (vitamin D3) in a highly concentrated form revolutionises the control of rodent pests.


Frequently asked questions - general information

Primary/secondary poisoning in dogs, cats, birds - what is the risk?

The dose makes the poison! The lethal dose depends on the amount of ingestion of the active substance in relation to the body weight. As a rule, however, secondary poisoning is only likely if a number of dead rats/mice are eaten in quick succession. However, there is no anticoagulant that can be called harmless in this context. The removal of dead harmful rodents is the be-all and end-all in the prevention of secondary poisoning.

Is there an antidote for rodenticides?

Vitamin K

How do I know if there is resistance?

On the one hand, there are online overviews of recorded resistances (e.g. here: www.julius-kuehn.de). On the other hand, resistance can exist if baits are eaten but the infestation does not decrease. Rats are very cautious and do not change their food. Therefore, it is important to change baits only when no reduction of infestation is observed despite eating.

Single-feed or multi-dose?

All 2nd generation formulations above 30 ppm, as well as difethialone and brodifacoum below 30 ppm are effective at single ingestion.

Where can I use rodenticides as a farmer?

Basically dependent on the approval of the product, please be sure to observe the product label.

How do I best control rodents in an open stable, next to many fields?

Equip entry routes with bait stations, clear away alternative food sources, cover access routes to buildings (cracks, crevices etc.) with rat foam.

Are new active substances to be expected?

There is currently no information on this.

What mistake am I making if I definitely have a rat infestation but the baits are not being eaten?

Too many alternative food sources that taste better; wrong placement of bait boxes; bait is no longer fresh. Rats are very cautious, it may take them a while to get used to the bait.

At what time of the year is it most sensible to control them?

An increased incidence is to be expected in the cold months with little natural food supply. Attentive monitoring throughout the year, e.g. with baits without active substances, prevents a surprising, massive infestation.

What is the difference between 1st and 2nd generation agents?

The toxicity and thus the effectiveness is higher with 2nd generation agents. In addition, there are more resistance areas with 1st generation active substances due to the one-sided and long-term application.

What should I do if my dog/cat has eaten a bait or a rat has eaten the rat bait?

In any case, observe the animal to see if it is reluctant to eat or move. To be on the safe side, consult a veterinarian and take the product label with you.

Is it true that maize neutralises the effect of rat medication?

100 g of maize contain 40 micrograms of vitamin K. Rodents would have to ingest a huge amount of maize to get 5 mg of vitamin K. This will usually not be possible and therefore maize has no effect unless the rodents are resistant to the active ingredient used.

How can one determine whether resistance is present?

Rats: depending on region/location (current resistance maps: https://guide.rrac.info/de/resistenzkarten.html).
Mice: if no lasting change in infestation is observed upon acceptance from the bait.

What is the stop-feeding effect? | Advantages and disadvantages?

Feeding ceases after just 2–3 days, resulting in the following benefits:

  • significant savings on bait
  • cessation of the consumption of alternative food sources

However, to achieve this stop-feeding effect, particular care must be taken during the initial baiting. It is crucial to provide sufficient bait; otherwise, control measures cannot be resumed until approximately 14 days later.


Frequently asked questions - documentation

Do I have to document the fight?

Yes, professional users are subject to a documentation obligation when using rodenticides. The documentation must in any case show the location, the target, the biocidal products used (product and quantity) and the persons carrying out the pest control. The documentation must be kept for at least 5 years.