Rodents

INCORPORATED 1987

ACCREDITED
APCA Members are required to possess TAFE or APCA Pest Control Certificate and extensive field work experience in the pest control service industry

Australian Pest Control Association

APCA Pest Control Certificate course details

Week 2 - Day 7 - Rodents - Rats & Mice

ESSENTIAL READING BEFORE COMMENCEMENT OF COURSE:

Urban Pest Management in Australia:
2004 Edition, UNSW Press, Sydney

by J Gerozisis and P Hadlington - Chapter 14 - pages 181 to 192.

Chapter 14 – Rats and Mice - biology and habits - rats and mice as pests - eating and contamination of stored foods - gnawing: physical damage - disease transmission - the important pest rodents - norway rat - roof rat - house mouse - detection of rats and mice - droppings - runways - burrows - gnawings - nests - runs - tracks - urine stains - urinating pillars - disappearance of food - sounds - visual sightings - excitement of pets - rodent control methods - non-chemical control - sanitation - rodent-proofing - trapping - simple snap traps - multiple-mouse-catching-devices - glueboards - chemical control - chemical baits - tracking powders and gels - fumigants - rodent control by chemical baiting - using traditional acute poisons - prebaiting - baiting - acute rodenticides - using multiple - dose anticoagulant rodenticides - mode of action - types of formulations - baiting - using single - dose anticoagulant rodenticides - safety precautions in rodent control.

Pest status: Rats and mice are notorious disease carriers - they contaminate food and homes with their feaces and urine - they are incontinent and leave urine trails as they roam - restaurants and food handling premises can face Health Department prosecution and a bad reputation if infested with rats or mice.

Three main pest species in Australia and world-wide:

Norway rat - Rattus norvegicus - also known as brown rat, sewer rat and wharf rat.

Roof rat - Rattus rattus - also known as black rat and ship rat.

House mouse - Mus musculus or Mus domesticus.

Distinguishing features

Norway Rat - stocky body - adults weigh about half a kilo - slightly larger animal than the roof rat - makes burrows - found wherever humans live - blunt nose - small close set ears which do not reach the eyes when pulled down - semi-naked scaly tail which is shorter than the head and body combined - coarse fur brownish, reddish-gray or blackish on top - whitish-gray under belly.

Roof Rat - slender body - tail as long as body and head combined.

House mouse - small slender - slightly pointed nose - black protruding eyes - large, scantily haired ears - nearly hairless tail with obvious scale rings - adult about 2/5 to 4/5 ounces - generally grayish-brown with a gray or buff belly - some are white-footed - jumping mice have a white belly - harvest mice have grooved upper incisor teeth.

Rodent senses – physical abilities

Excellent hearing, smell, taste and touch: Rats have poor eye-sight beyond three or four feet - excellent sense of hearing, smell, taste and touch - highly sensitive to motion up to 30 to 50 feet away - use sense of smell to locate food items and recognize other rats - rely on their sense of smell to recognize odors of pathways, members of the opposite sex who are ready to mate, differentiate between members of their own colonies and strangers, and to tell if a stranger is a strong or weak individual.

Hearing: Norway rats use hearing to locate objects to within a few inches. This highly developed sense, combined with their touch sensitivity, can pinpoint someone rolling over in bed to a six inch area. The frequency range of their hearing (50 kilohertz or more) is much higher than that of humans (about 20 kilohertz.)

Touch: Norway rats have a highly developed sense of touch due to very sensitive body hairs and whiskers which they use to explore their environment. Much of a rodent’s movement in a familiar area relies heavily on the senses of touch and smell to direct it through time-tested movements learned by exploration and knowledge of its home range. Rodents prefer a stationary object on at least one side of them as they travel and thus commonly move along walls, a fact which is very useful when designing a control program.

Taste: Their sense of taste is excellent, and they can detect some contaminants in their food at levels as low as 0.5 parts per million. This highly developed taste sensitivity may lead to bait rejection if the rodent baits are contaminated with insecticide odors or other chemicals.

Characteristic	Norway rat	Roof rat	House mouse
Weight	450 gms	260 gms	20 gms
Body	Heavy	Slim	Small
Nose	Blunt	Pointed	Pointed
Ears	Small	Large	Large
Tail to body length	Shorter than body and head	Longer than body and head	Same length as body
Fur colour	Red to brown	Grey to black	Brown to grey
Gestation period	22 days	23 days	19 days
Number of litres	5 to 6 per annum	4 to 5 per annum	6 to 10 per annum
Average life span	1 year	1 year	1 year
Range	40 to 50 metres	40 to 50 metres	3 to 10 metres
Preferred food	Omnivorous Garbage, cereals, meat, fish	Omnivorous Vegetables, fruits, cereal grains	Omnivorous Cereal grains
Food Intake	20 to 30gms a day	15 to 22gms a day	3gms a day
Water Intake	20 to 30ml a day	15 to 22 ml a day	1ml a day

Types of rodenticides

Ready-to-use-baits: mostly in the form of treated whole grain or pellets, available in bulk or throw-pack form.

Concentrates used in the preparation of food or liquid baits, or perhaps as a tracking powder.

Paraffin blocks usually treated grain matrix of paraffin wax, suitable for areas with excessive moisture.

Bait stations available - Protecta lockable - cardboard.

Signs of a rats or mice infestation: Since rats and mice are active at night and are rarely seen during the day, it is necessary to recognise signs of their activity.

Droppings and urine: Most people first recognise rodent problems by finding droppings or urine stains in and around buildings. Rodents usually have favorite toilet areas but will void almost anywhere. Old droppings are grey, dusty, and will crumble. Fresh droppings are black, shiny, and putty like. Rodents urinate while running, and the streaks are characteristic. The urine glows under ultraviolet lights and glows blue-white when fresh. A good indicator that the rodents are taking the bait is the change in colour of their droppings.

Gnawed objects: Rodents gnaw every day in order to keep their teeth short and sharp. Rats also gnaw to gain entrance or to obtain food. Teeth marks on food, building materials, wire, and edges of beams are indications of gnawing. They gnaw holes in wooden walls, pressed wood, and posts. Fresh gnawing in wood is usually light-coloured with sharp, splintery edges. Old gnawing is smooth and darker.

Runways: Rats habitually use the same paths or runways between harbourages and food or water. Outside runways and paths 2 to 3 inches wide and appears smooth, hard packed trails under vegetation. Indoor runways are usually found along walls. Undisturbed cobwebs or dust indicates that the runways are not in use.

Rubmarks: Along runways, dark greasy rubmarks appear from contact with the rodent’s body. Rubmarks on walls appear as black smudges left by the rodent. New rubmarks are soft and will smudge. Old rubmarks are brittle and will flake when scratched. Rafters may show swing marks of roof rats.

Tracks: To detect rodent activity, spread dust material like talcum powder along obvious or suspected runways. Inspect any animal foot prints found - note rats have 4 toes on front feet and 5 toes on hind feet - also rat tail drag marks will show in the powder.

Burrows: Norway rats burrow for nesting and harbourages. Burrows are usually found in earth banks, along walls, under rubbish and concrete slabs. Freshly dug dirt scattered in front of 3 inch openings with runways leading to the openings are characteristics of these pests. Burrows usually are 18 inches deep in most soils. Slick hard packed runways indicate an old established colony.

Live rats and any dead rats: The sighting of live rats is a sure sign of infestation. Sightings in daylight indicate that there is a large infestation. Mummified rat carcasses may indicate a former infestation although many fresh carcasses suggest disease or poisoning.

Sound: Usually rodent sounds are heard at night or in quiet areas. Rodents moving at night often scratch, gnaw, and fight. The young often squeak while in the nest.

Pets: Usually dogs or cats will act strangely, especially at night, if rodents are present.

Food Processing Factories

Rats and mice are among the most significant of all pests in the food and warehousing industry. Food plants are subject to varying levels of "rodent pressure" depending on several factors. As a result, plants must be unrelenting in their rodent control programs. Food plant rodent IPM programs include a combination of baiting, trapping, proofing and sanitation compliance procedures

Long term benefit: Sanitation and rodent proofing are the most emphasized elements for long-term, cost-effective results.

The three lines of defence program involves property line baiting or trapping, exterior wall baiting or trapping lines, and mousetraps lining the interior perimeter walls of the food plant or warehouse. The choices of specific stations bait formulations, and traps, as well as the specific instalments and servicing of all these devices, are all important considerations to ensure thorough protection of the plant from rodents, as well as providing cost-efficient programs.

Consequently, a significant amount of money is spent each year by the food industry in the purchase of rodent control equipment and the services associated with the set-up, maintenance, and servicing of the equipment. In the majority of many plants and warehouses, the rodent control program alone comprises the bulk of the entire annual pest management costs.

Physical Control in Buildings: Rodent Proofing: The most permanent method of rodent control is to modify the building to ensure they can no longer have access to the building. You will have to start off by carrying out a very thorough inspection of the building/buildings, locating cracks, crevices, holes and other potential access points that could allow the entry of rodents. Strong sturdy building materials such as cast iron heavy gauge steel durable metals and rich cement mortar or concrete mixes.

Trapping is an underrated method of controlling rodents. One reason trapping is often overlooked is that snap traps have been around for a long time and are cheap. Traps can be used to eliminate rats where poison baits would be dangerous, to avoid dead rat odours, and to eliminate bait-shy rats.

It is important to place traps where the rats are. Rats and mice are used to human odours so there is no need to use gloves when handling traps. Since mice travel only 3-10 metres but rats travel 30-50 metres from harbourages, more traps are needed to trap mice than rats in a building.

Rats and mice also have different behaviour around new objects. Rats are cautious, and it may take a week before they approach a trap. Mice are curious and will normally approach traps on the first night. If you do not catch a mouse in the first few nights, then the trap is in the wrong location. To help rats overcome trap shyness, place traps unset, in place for several days. This allows the rats to overcome shyness and results in better catches.

Bait attractiveness? Baited traps rely on the rat’s being attracted for feeding. The bait must compete with other available food, so no one bait is ever the best for all locations. Rodents living on garbage or spoiled food prefer something fresh, when in doubt, look at what products or food sources that they have already attacked in the building to get an idea of a food source that you can lure them into. The following are baits that have proven successful in the past:

Whole nuts for rats and mice.
Raisins or grapes for roof rats.
Sardines packed in oil for Norway rats.
Peanuts or peanut butter for rats and mice (soak whole peanuts in water overnight; old peanut butter becomes rancid so replace it frequently).
Dry rolled oatmeal is excellent for mice.
Bacon squares
Small wads of cotton for mice and rats (they look for nesting material).
Gumdrops for mice
Vanilla essence placed on rodent blocks.

Baited traps should be set at right angles to rat runs, traps can be nailed to rafters and beams to take advantage of areas where rats travel. Set traps along walls, behind furniture, and near holes. Remember to set traps where children and pets will not be hurt.

Runway traps: These catch rats when they accidentally bump the trigger. Runway traps are available or can be made from snap traps by enlarging the trigger with cardboard or something similar. The benefit of this way is that there is no bait to go stale, therefore a good chance of success. In placing runway traps, the trap should be placed at right angles to the wall or along runways. To hold the trap in place on pipes or rafters, use rubber bands, nails, or hose clamps.

Chemical Control

Single dose anticoagulant rodenticides: Give good control in small amounts and single feedings. A single lethal dose ingested by a rat will cause death in 3-7 days.

Multiple dose anticoagulant rodenticides: The effects of this rodenticide are cumulative, requiring rodents to feed on the bait for several consecutive days. Death will vary, normally in 4-10 days.

Chemical control - baits - tracking powders - gels - pastes - fumigants

Chemical Baits: Rodent control by chemical baiting is normally carried out in the form of a wax block, granulated pellets or gel/paste formulation, liquid baits which would be placed in a lockable container for children and pets safety in Australia.

Tracking powder may be used in two formulations, one way is it may be mixed into a cake formulation with some of the food sources that the rodent has been attacking eg 1:20 ratio, and the other is as it is called a tracking powder, the powder is gently and finely sprinkled over known areas where the rodents have been sighted, and the rodent grooms itself, and inturn suffers from oral poisoning. Care must be taken that the tracking powder does not end up on any food surfaces or areas where food may be contaminated.

Gels and pastes may be used in exactly the same way as wax blocks, they may even be placed in roof voids by themselves in areas where non targeted animals may gain access.

Fumigants these would only be used if a large infestation was present and rapid elimination is required, for example a chicken farm, normally treating burrows, using phosphine.

Liquid Baits: These formulation baits are mainly used in the preparation of food baits, but can be used alone as a liquid drink for rodents.

Mode of Action: Most rodenticides are anticoagulants, which reduce the ability of rodent’s blood to clot. Basically this process reduces the amount of vitamin K1 in the rodent’s body. Internal body damage that occurs normally and would normally be checked for clotting becomes lethal. The reaction can be reversed, by qualified medical personnel, by the means of vitamin K1.

Safety Precautions

Rodenticides are harmful to humans and pets, they are tested on rats and mice, as they have similar internal body organs as humans, therefore what will harm a rodent will harm a human, so extreme caution must be exercised when using rodenticides.eg:

Always read and heed the label
Store rodenticides in their original containers
The rodent stations must be labelled with POISON and numbered.
A map be supplied to owner showing location of bait stations (numbered).
Baits must be replaced so that they can be recovered.
Baits must not be placed where children and pets, domestic and wildlife do not have access, this might mean that specially designed security containers are supplied.
Do not place baits or tracking powders where their disturbance could cause food contamination.
Always wear protective clothing when handling rodent baits.
Always try to keep baits away from a food source
Do not contaminate ponds, waterways, or drains, with rodenticides
Do not eat , drink, or smoke whilst handling tracking powders.

Non-chemical methods: In some commercial situations baiting with rodenticides is not allowed or is not preferred or occasionally the rodents will not take the current baits. Some situations where baits are not allowed or should not be used are where there can be no dead animal odour; a rodenticide may be dangerous to humans, domestic animals or the environment; rodents have developed a bait shyness; or where there is a threat of food contamination.

Products Available for Non-Chemical Control include Mouse Master; Tin Cat; Mini Cat; Snap Traps; Glue Boards and Bristle Strips

Mouse Master: For the most practical professional pest control service, use the multi-catch trap. Just set it against the wall with openings running either way. The Mouse Master is wound up by a key type system, which when the mouse steps on to a plate it forces it very quickly into a confinement area, this action immediately sets the trigger pan for the next mouse.This system holds approximately 10 mice per trap.

Tin cat: a low profile design, for placement under shelves, pallets, or in shallow ceiling voids. This trap has a trap door and may hold approximately 30 mice.

Mini cat: This product is similar to the Tin Cat but only smaller, and made from plastic, it can hold up to three mice.

Snap traps: These traps are normally made from wood or plastic, or both. They are based on the guillotine action and kill immediately they are a low cost system, and it is normal to place an attractant such as nutella or peanut butter on the food plate. They are normally placed in runways; boxes or stock may be moved to funnel in the rodents to the trap.

Glue boards: These are traps used for mice and rats. Commercially prepared glue boards are expensive, so proper placement is important. After getting caught, most rodents get their nose inthe glue and die of suffocation. The disadvantages of glue boards are that dust conditions will cover the glue board, so they may have to be covered. When covered in dust, the glueboard can be re-newed by wiping the surface with a rag which has vegetable oil on it.

Bristle strip: A proofing program always complements a successful rodent service; whether it is carried out by the customer or by the technician is irrelevant. Bristle strips can be purchased at any local hardware and normally cut to any desired length this point should always be raised with the customer. Bristle strips are normally used on the bottom of doors or any situation where a gap can be minimised.

AVPMA Registered Rodenticide labels

Talon Wax Blocks.

Stratagem wax blocks.

MSDS Material Safety & Data Sheets

Talon Wax Blocks.

Ditrac Wax Blocks.

Contrac Wax Blocks

Stratagem Wax Blocks

Talon wax Blocks

AQIS Approvals

Talon Wax Blocks.

Contrac Wax Blocks.

Ditrac Wax Blocks.

Talon Wax Blocks

References - websites

Consumer Guide - Rats & Mice - describes rodent pest species in Australia - pest status - biology - habtat areas - practical pest control tips - cost of professional service.

House mouse prevention and control - Illinous Dept Health

Rats - indentification - biology life cycle - damage - control - California University

Rodent control in poultry houses - Mississippi University

Rodent control, IPM, biology - Antec International

References - PDF downloads

Bait stations for rats & mice - Nebraska University

Fumigation of rodent burrows - Nebraska University

House Mouse - indentification - ecology - biology - control - California University

Norway rat - indentification - ecology - biology - control - California University

Rats - proofing and trapping - San Mateo County

Rodent control - Hybrid

Rodent control and safe use of rodenticides - UK Govt HSE