Where it is impossible to exclude rodents from structures, rat control can be accomplished by establishing permanent bait stations in buildings and around the perimeters of buildings. Prevention and Control of Wildlife Damage, Vol. Symptoms of anticoagulant poisoning in mammals include lethargy, loss of color in soft tissues such as the lips and gums, and bleeding from the mouth, nose, or intestinal tract. They have poor eyesight, but they make up for this with their keen senses of hearing, smell, taste, and touch. Their edges can be covered with sheet metal if gnawing is a problem. Salmon, T. P., D. A. Whisson, and R. E. Marsh. See our Home page, or in the U.S., contact your local Cooperative Extension office for assistance. Get PDF Reader Accessibility Thus, they often avoid traps and baits for several days or more following their initial placement. Nondiscrimination Statement, Accessibility These official UC-approved guidelines for pest monitoring techniques, pesticide use, and nonpesticide alternatives for agricultural crops are essential tools for anyone making pest management decisions in the field. Pest Notes are peer-reviewed publications about specific pests or pest management topics directed at California's home and landscape audiences; they are based on UC's IPM … Pest Notes contain information on how to identify the pest, its biology and habitat, life cycle, damage and impact, and include multiple management suggestions. Both species can share some of the same food resources but don’t feed side by side. . Glue traps, which work on the same principle as flypaper, aren’t recommended for controlling rats, as they are much less effective for rats than for mice. Key characteristics Otherwise, for other technical issues, use our Campus Help page for assistance. Are there rat or mouse droppings in your recycle bins? If sanitation measures aren’t properly maintained, the benefits of other measures will be lost and rats will quickly return. Good housekeeping in and around buildings will reduce available shelter and food sources for Norway rats and, to some extent, roof rats. . Oakland: Univ. In S. E. Hygnstrom, R. M. Timm, and G. E. Larson, eds. Changes in rodenticide regulations went into effect in mid-2011 in an effort to prevent rodenticide hazards to wildlife and pets and to reduce accidental exposure to children. When such baits are in use, extra caution is needed, as exposure to even a single dead rodent might be enough to poison a pet. Subscribe (RSS) UC IPM Pest Management Guidelines: Lettuce UC ANR Publication 3450 S.T. garden or landscaping, unless your house is truly rodent proof, Get Flash Player You can pick them up using a sturdy plastic bag inverted on your hand, seal them in the bag for disposal with household garbage, or bury them in a location where pets or scavengers won’t easily dig them up. Where dogs are kept and fed outdoors, rats can become a problem if there is a ready supply of dog food. pp. Pest Notes: Voles (Meadow Mice). All rights reserved. In homes, the attic and garage rafters close to the infestation are good trapping sites. In addition to increasing the safety of the bait, bait stations also help the rats feel secure while feeding. All rodent baits are toxic to dogs and cats, so be cautious when using these products. Timm, R. M. 1994. In many cases, bait stations must be resistant to destruction by dogs and by children younger than 6 years old and must be constructed in a manner that prevents a child from reaching into the bait compartments and getting the bait. These two materials are formulated to serve as chronic rodenticides so that rats will have the opportunity to feed on exposed baits one or more times over a period of one to several days. Even glue can be used to secure the bait to the trigger. Coarse steel wool, wire screen, and lightweight sheet metal are excellent materials for plugging gaps and holes. Fasten the bait securely to the trigger of the trap with light string, thread, or fine wire so the rodent will spring the trap when attempting to remove the food. Nat. Sanitation is fundamental to rat control and must be continuous. Nondiscrimination Statement. in or falling from the trees in your yard? When prepared with good-quality cereals and other ingredients, anticoagulant baits provide good to excellent control when baits are fresh and when placed in suitable locations so as to attract rats. Authored by University scientists, each Pest Note is peer reviewed through the UC ANR process. Publ. Rats can grab food and carry it off to feed elsewhere. When the two species occupy the same building, Norway rats may dominate the basement and ground floors, with roof rats occupying the attic or second and third floors. Lincoln: Univ. While trapping is generally recommended for controlling rats indoors, when the number of rats around a building is high, you might need to use toxic baits to achieve adequate control, especially if there is a continuous reinfestation from surrounding areas. IPM programs focus on preventing pest problems by getting rid of the food, water and shelter that pests need to survive. As you would with any poison, take care to ensure safety to children and pets by limiting their access to the bait. They quickly detect and tend to avoid new objects and novel foods. In all cases, the user must follow label directions. Homes, Gardens, Landscapes, and Turf > While rats are much larger than the common house mouse or meadow vole, a young rat is occasionally confused with a mouse. Use disposable gloves to handle dead rodents. Container Gardening (Ornamentals) 23. They’ll often eat the rind of a lemon, leaving the flesh of the sour fruit still hanging. Norway rats, Rattus norvegicus, sometimes called brown or sewer rats, are stocky burrowing rodents that are larger than roof rats. Citrus: UC IPM Pest Management Guidelines This free publication is available as a web page or downloadable PDF document . The roof rat has a more limited geographical range than the Norway rat, preferring ocean-influenced, warmer climates. Calif. Agric. Publ. Snap traps with large plastic treadles are especially effective, but finding the best locations to set traps is often more important than what type of trap is used. New nematode to California. When rodenticides (toxic baits) are used in structures, rats can die in inaccessible locations such as within walls or ceilings. When used indoors, cats and dogs can get into the glue and track it around the house; outdoors, glue traps can capture lizards, birds, and other nontarget wildlife. Some baits must be contained within bait stations for all outdoor, above-ground applications. Put bait in locations out of the reach of children, pets, domestic animals, and nontarget wildlife or in tamper-resistant bait stations as required by the product label. A dozen or more traps for a heavily infested home might be necessary. Make sure doors, windows, and screens fit tightly. Collect garbage, trash, and garden debris frequently, and ensure all garbage receptacles have tight-fitting covers. Droppings, gnawings, and damage indicate the presence of rodents, and areas where such evidence is found usually are the best places to set traps, especially when these areas are located between their shelter and food sources. between Norway and roof rats. They can live in trees or in attics and climb down to a food source. For Norway rats, set traps close to walls, behind objects, in dark corners, and in places where rat signs, such as droppings, have been seen. Unlike Norway rats, their tails are longer than their heads and bodies combined. Subscribe (RSS) the Garden, Mushrooms and Other Nuisance Fungi in Lawns, Phytophthora Root and Crown Rot in the Garden, Creeping Woodsorrel and Bermuda Buttercup, Roses: Cultural Practices and Weed Control, Biological Control and Natural Enemies of Invertebrates, Pesticides: Safe and Effective Use in the Home and Landscape, Pesticidas: Uso Seguro y Eficaz en el Hogar y en Jardines, Soil Solarization for Gardens & Landscapes. For controlling rats indoors, using traps is best. Seal all openings around pipes, cables, and wires that enter through walls or the foundation. Rats, like house mice, are active mostly at night. These traps need to be checked frequently, and dead rodents should be removed for disposal. Rat. Three other active ingredients are registered and used as rodenticides to control rats and house mice in California: bromethalin, cholecalciferol, and zinc phosphide. Anticoagulants have the same effect on nearly all warm-blooded animals, but the sensitivity to these toxicants varies among species with larger animals generally requiring a larger dose of toxicant than smaller animals. While the most permanent form of control is to limit food, water, shelter, and access to buildings, direct population control often is necessary. Live traps aren’t preferred, because trapped rats must be either humanely killed or released elsewhere. of Wildlife, Fish, and Conservation Biology, UC Davis. Norway rats can undermine building foundations and slabs with their burrowing activities and can gnaw on all types of materials, including soft metals such as copper and lead, as well as plastic and wood. Corrigan, R. M. 2011. Different designs of commercially manufactured bait stations may be required, depending on the particular situation and the bait formulation used. The simple, wooden rat-size snap trap is the least expensive option, but some people prefer the newer plastic, single-kill rat traps, because they are easier to set and to clean. A rodent feeding on anticoagulant bait usually won’t die until 2 to 6 days following ingestion of a lethal dose. While this secondary poisoning is possible, it isnt common with the first-generation anticoagulants. They have an excellent sense of balance and use their long tails to steady themselves while traveling along overhead utility lines. Marsh, R. E. 1994. Calif. Agric. Pest Notes are UC IPM publications written for people who want information about pests in homes, office buildings, schools, gardens, urban landscapes, and more. Norway rats eat a wide variety of foods but mostly prefer cereal grains, meats, fish, nuts, and some fruits. Pest Notes are peer-reviewed scientific publications about specific pests or pest management topics for California's residential and community audiences. Because Norway rat burrows can extend beneath a residence and have several open entrances, toxic gases can permeate the dwelling. Residential or industrial areas with mature landscaping provide good habitat as does riparian vegetation of riverbanks and streams. When pest management is needed, IPM uses a combination of common-sense, least harmful practices. When food, water, and shelter are available, rat populations can increase quickly. While both rats and mice gnaw on wood, rats leave much larger tooth marks than mice do. check for signs of their presence. Rats caught in glue traps can struggle for quite some time, often dragging the trap as they try to escape. All rodenticide baits must be used carefully according to the label directions, which have become more specific and more restrictive. Cover all chimneys with a spark arrester. The average female Norway rat has 4 to 6 litters per year and can successfully wean 20 or more offspring annually. Each publication includes colorful photographs or illustrations to help readers with identification and finding solutions. In general, very young rats have large heads and feet in proportion to their bodies, whereas those of adult mice are proportionately much smaller. Both Norway and roof rats can gain entry to structures by gnawing, climbing, jumping, or swimming through sewers and entering through toilets or broken drains. Norway rats can be drowned or flushed from their burrows by flooding them with water from a garden hose and then closing the holes with soil. Once published, each document is reviewed periodically, typically about every 5 years, and updated as needed. Rats are wary animals, easily frightened by unfamiliar or strange noises. If this is the case, consider hiring a licensed pest control applicator who is trained to use rodenticides safely. Once rats have invaded your Rats eat and contaminate foodstuffs and animal feed. See our Home page, or in the U.S., contact your local Cooperative Extension office for assistance. B.125–132. Agricultural producers and professional pest control personnel are able to obtain more types of rodenticides in various formulations, some of which are restricted use pesticides. Predators, especially cats and owls, eat rats and mice. PDF: To display a PDF document, you may need to use a For Norway rats, place bait stations near rodent burrows or suspected nest sites, against walls, or along travel routes. pp. Please visit the UC Statewide Integrated Pest Management Program (UC IPM) website for an extensive list of pest management and identification sites. To avoid using too few traps, if bait it taken from all traps, double the number of baited traps exposed, and keep doing so until some traps remain with bait untaken; then bait and set all traps. Baits and bait stations now have more restrictive regulations regarding locations for use. In buildings, they are most often found in enclosed or elevated spaces such as attics, walls, false ceilings, and cabinets. Roof rats, R. rattus, sometimes called black rats, are slightly smaller than Norway rats. For additional information on mice, see Pest Notes: House Mouse and Pest Notes: Voles (Meadow Mice). Do you see evidence of something digging under your garden A major drawback with glue boards and other live-catch traps is the trapped rat might not die quickly, and you will need to kill it by delivering a sharp blow to the base of the skull using a sturdy rod or stick. will be required if control is started early. For example, some labels state “tamper-resistant bait stations must be used if children, pets, nontarget mammals, or birds may access the bait.” Certain prepackaged bait stations intended for sale to homeowners can be used only inside structures and are prohibited for use in any area accessible to pets or outdoors. For roof rats, the best places for traps are off the ground in locations where rats might be coming down from their nests to find food—such as on ledges, shelves, branches, fences, pipes, or overhead beams—where they can be fastened with screws or wire. FOR ALL OTHER USES or more information, read Legal Notices. pool or hot tub? For noncommercial purposes only, any Web site may link directly to this page. Releasing rats outdoors isn’t recommended, as they can cause health concerns to people, pets, and other domestic animals. Clearly label all bait stations with appropriate warnings, and store unused bait in a locked cabinet or another area inaccessible to children and domestic animals. Norway and roof rats don’t get along. Neb. UC IPM Avocados UC IPM Phytophthora Root and Crown Rot in the Gard... 19. Calif. Agric. The Mallis Handbook of Pest Control, 10th ed. The best precaution is to keep pets away from bait and dead or dying rodents. Staff-only pages The Norway rat is larger and the more dominant species; it will kill a roof rat in a fight. Generally, young rats can’t be trapped until they are about a month old, which is when they leave the nest to venture out for food. Statewide IPM Program, Agriculture and Natural Resources, University of California Their burrows are found along building foundations, beneath rubbish or woodpiles, and in moist areas in and around gardens and fields. Acknowledgements Staff-only pages Subscribe (RSS) Contact UC IPM INSECTS Acidification of tank mix to enhance the efficacy of organically registered pesticides for control of spotted wing drosophilia, Drosophilia suzukii :: Crop Notes newsletter (Jan.-Feb. 2010) PDF reader. Contact webmaster. They eat and contaminate food, damage structures and property, and transmit parasites and diseases to other animals and humans. IPM If a rat sets off a trap without getting caught, it will be very difficult to catch the rat with a trap again. Place all bait stations in rat travel ways or near their burrows and harborage. Res. If the answer to any of This slow action is a safety advantage, allowing accidental poisoning to be treated before serious illness occurs. Gardening in Crisis: An American For roof rats in particular, thinning dense vegetation will make the habitat less desirable. Make sure all exterior doors are tight fitting and weatherproofed at the bottom. Res. Peer-reviewed publications Sutherland, A.M., Choe, D-H, Rust, M.K. They have been known to decimate some bird populations. Concerns about both primary and second hazards of second-generation anticoagulant baits led the EPA to restrict their retail sale in mid-2011, making them available only to agricultural users and professional pest control personnel. Natwick (emeritus), UC Cooperative Extension … Nat. Most fatalities in pets involve dogs and are due to the animal eating the bait directly (primary poisoning) or a combination of direct bait consumption and secondary poisoning. Roof rats are especially fond of avocados and citrus, and they often eat fruit that is still on the tree. Provide a tight-fitting cover for the crawl space. Since not all rats will consume bait when it first becomes available, bait application directions typically recommend providing an uninterrupted supply of bait for at least 10 or 15 days or until evidence of rodent activity ceases. The best places to set traps are in secluded areas where rats are likely to travel and seek shelter. tool shed or doghouse? All contents copyright © Roof rats prefer to nest in locations off the ground and rarely dig burrows for living quarters if off-the-ground sites exist. Like Norway rats, roof rats eat a wide variety of foods, but they prefer fruits, nuts, berries, slugs, and snails. Dispose of dead rats by burying them or by placing them in a sealed plastic bag and putting them in the trash. Other baits or bait stations may also be used around the periphery of structures or within 50 feet of a structure. it is only a matter of time before you find evidence of them indoors. There are no truly effective rat repellents registered for use in California. Experience has shown it is less time consuming to control rodents Res. garage? Baits to control rodents are formulated with an attractant (generally food) and a rodenticide (toxin). Because of the potentially greater hazard of second-generation anticoagulants to children and household pets, these active ingredients are no longer allowed to be manufactured for sale to the general public. Place rat traps about 10 to 20 feet apart. Acknowledgements (See Pets and rat control.). Among the diseases rats can transmit to humans or livestock are murine typhus, leptospirosis, salmonellosis (food poisoning), and ratbite fever. Because rats often are suspicious of new or unfamiliar objects, it might take several days for them to enter and feed in bait stations. In areas where the roof rat occurs, the Norway rat might also be present. These federal EPA restrictions now permit manufacturers to produce, for sale to the general public, only wax block, gel, or paste rat and mouse baits that are packaged in ready-to-use, disposable bait stations. If you place bait stations above ground level, take care that they are securely fastened and won’t fall to the ground where children or pets could find them. If traps are set parallel to the wall, they should be set in pairs to intercept rodents traveling from either direction. Traps can be set and left indefinitely in areas such as attics where rats have been a problem in the past. When feeding on a mature orange, they make a small hole through which they completely remove the contents of the fruit, leaving only the hollowed-out rind hanging on the tree. The Regents of the University of California. Unfortunately, we cannot provide individual solutions to specific pest problems. The various anticoagulant active ingredients currently registered for use against rats in California are listed in Table 2. Rats constantly explore and learn, memorizing the locations of pathways, obstacles, food and water, shelter, and features of their environment. They often can be seen at night running along overhead utility lines or fence tops. Turini, UC Cooperative Extension Fresno County Acknowledgement for Contributions to Diseases In A. Mallis, D. Moreland, and S. A. Hedges, eds. Oakland: Univ. before their numbers get too high, and fewer traps and less bait Remove and properly dispose of all uneaten bait at the end of a control program. In S. E. Hygnstrom, R. M. Timm, and G. E. Larson, eds. The UC also has a series of Pest Notes, though a careful reading is required, since pests’ seasonal activities varies, as does their management. Have you found remnants of rat nests when dismantling your Unfortunately, we cannot provide individual solutions to specific pest problems. Staff-only pages Seal cracks and openings in building foundations and any openings for water pipes, electric wires, sewer pipes, drain spouts, and vents. Set traps so the trigger is sensitive and will spring easily. 21385. Their favorite habitats are attics, trees, and overgrown shrubbery or vines. against beams, rafters, pipes, and walls? E. Walton, Entomology and Pacific Southwest Center of Excellence in Vector-borne Diseases, UC Riverside; and Bruce F. Eldridge, Entomology, UC Bed bugs can be distinguished from their close relatives bat bugs and swallow bugs by comparing the length of the hairs on the pronotum to the diameter of the eye; this requires a hand lens or microscope. Soft baits such as peanut butter and cheese can be used, but rats sometimes take soft baits without setting off the trap. Because snap traps can be used over and over, trapping is less costly than poison baits but more labor intensive. Nests can be lined with shredded paper, cloth, or other fibrous material. 1. In areas where children, pets, or birds might contact traps, place the trap in a box or use a barrier to keep them away. Contact UC IPM, Agriculture and Natural Resources, University of California, © 2019 Regents of the University of California Some house cats don’t have the ability or inclination to prey on adult Norway rats. If you are unsure of the species, look for rats at night with a bright flashlight, or trap a few. For noncommercial purposes only, any Web site may link directly to this page. Many of the methods and materials used to control rats can affect pets as well. Check bait stations regularly and replace bait if it gets old or moldy, because rats won’t eat stale bait. The average number of litters a female roof rat has per year depends on many factors, but generally it is 3 to 5 with 5 to 8 young in each litter. Don’t expect rats to go out of their way to find the bait. Neb. Climbing hedges such as Algerian or English ivy, star jasmine, and honeysuckle on fences or buildings are conducive to roof rat infestations and should be thinned or removed if possible, as should overhanging tree limbs within 3 feet of the roof. Because neither the roof rat nor the Norway rat is native to the United States, their presence in the wild is very detrimental to native ecosystems. It’s important to know which species of rat is present in order to choose effective control strategies. While both species exhibit this avoidance of new objects, this neophobia is usually more pronounced in roof rats than in Norway rats. Traps that kill rats by electrocution (e.g., Rat Zapper or Victor Electronic traps) are considerably more expensive than other traps, but some homeowners, managers of commercial buildings, and pest control companies have found them to provide good results. Lincoln: Univ. 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