Training Manual on Integrated Rodent Pest Management

Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 1 Training Manual on Integrated Rodent Pest Management By Dr. Namala Srinivasa Rao Dr AMK Mohan Rao Dr P.V.Satyanarayana B.Anusha Andhra Pradesh Rice Research Institute& RARS Maruteru534122, West Godavari Dist., Andhra Pradesh Acharya N G Ranga Agricultural University Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 2 INTRODUCTION Order Rodentia makes up almost 40 per cent of mammal species and represent the largest order of mammals, comprising >2000 species in 34 families that include 389 genera throughout the world. In India, 4 families (Sciuridae, Dipodidae, Muridae and Hystricidae), 43 genera, and 104 species represent rodents. Among them about 14 species are of economic importance. Rodents are agricultural, storage and household pests throughout the country causing direct damage to various commodities by gnawing and feeding and indirect damage by spoilage. They are the most important ones among vertebrate pests due to their high adaptability to live successfully in man-made environments. The group is given the name due to their gnawing teeth (Rodere = to gnaw; dent = teeth), which provide them access to closed places and packaging material and food sources. Since they are prolific breeders and the young mature quickly their presence could be felt by their damage to edibles and non-edibles that make humans to go for their control. Further, their cryptic life style and relatively small body size tend to complicate their control activities. Since they are also mammals, safety considerations in relation to the human population also keep a tab on the usage of rodenticides. Urban areas, the houses, animal sheds and food stores provide permanent source of food and shelter to these pests due to their poor quality. Control actions in such conditions are very difficult since they require inputs for efficient proofing operations. Proofing will often be done poorly or with inefficient material resulting in free access for rodent entry into these buildings/structures. Normally people expect that control actions should kill visibly large number of rodents. Thus, they would like to see immediate result of the action. Habitat manipulation, sanitation operations or preventive control and the use of modern anticoagulant rodenticides do not result in visibly dead animals. As a result, most of them doubt the affectivity of control actions. In many cultures, humans developed tolerance to rodents and accept them as a fact and they rarely understand the close relation between rodents and certain diseases. In other places, rodents are an important source of proteins or they are even worshiped. These facts make it imperative of motivating local community for bringing out effective rodent control results. Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 3 I. ECONOMIC IMPORTANCE OF RODENTS IN AGRICULTURE In India, rodents are serious pests in fields and in human dwellings, both in the countryside and in cities. They cause serious damage to crops before and after harvest, damage installations and are reservoirs or vectors of serious infectious diseases. Rodents cause direct damage to various crops/commodities by gnawing and feeding and indirect damage by spoilage, contamination and hoarding during on-farm and post harvest stages. Knowledge of the characteristics, extent of damage and vulnerable period for rodent attack in different crops and situations is important for appropriate planning of management strategies. 1.1 Pre harvest Losses Most of the standing crops are vulnerable to rodent damage in India (Parshad, 1999; Rao and Joshi, 1986). However, the pattern, extent of damage and their level of infestation vary in different crops and geographical regions. Most of the estimates of damage relate to isolated studies in smaller plots and extrapolated to larger areas. They cause damage at almost at all stages of cereal crops from sowing to harvest. Both chronic damage and outbreaks of rodents affect the cereal production significantly in the country. The chronic losses often go un-recognised and these losses are economically more important. Hart (2001) reported that the overall losses of grain to rodents in India were approximately 25% in pre harvest and 25-30% in post harvest situations bringing the loss to at least US$ 5 billion annually in stored food and seed grain in India. 1.1.1 Cereal crops Irrespective of the type of rice production system viz., irrigated, wetland, upland (terrace) or deep water, rodents cause considerable damage to rice crop in India like in other South Asian countries. The analysis of the reviews on pre harvest losses indicates a range of 5-15% damage to cereal crops like rice and wheat. The lesser bandicoot rat, Bandicota bengalenis is the predominant rodent pest in these crops. The vulnerable crop period is boot leaf stage due to availability of sweaty mucilage and crop compensation will be absent after this stage. 1.1.2 Pulse and oilseed crops Incidence of moderate to severe damage to the pods of lentil, arhar, moong, soybean and Bengal gram are common because of high protein content of seeds. Changing patterns of agricultural practices made pulses vulnerable for rodent damage. Introduction of summer pulses between rabi and ensuing kharif season makes continuous availability of food for rodents that makes them to breed even during summer, increasing their population and making the area as endemic for these pests. Several areas in the country became endemic to rodents mostly because of this change in agricultural practice. Awasthi and Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 4 Agarwal (1991) reported a yield loss of 16.5 kg. /ha in soybean crop at green pod stage, which is vulnerable stage of the crop. Groundnut is grown as irrigated dry crop in most of the areas in the country. Rodents damage and remove the pods at sowing time and at maturity and hoard sometimes up to 320 g/burrow. Indian gerbil, Tatera indica and soft furred field rat, Millardia meltada along with B. bengalensis in irrigated fields cause the major damage. 4-7% of damage is documented to pods. During the population outbreak of T. indica, M. meltada and B. bengalensis during 1976 and 1988-89 in Gujarat rodents damaged up to 85.42% of the crop in Saurashtra area. 1.1.3. Sugarcane Sugarcane is grown in 5.3 lakh hectares with a production of 380.71 lakh tones. Rodents damage sugarcane crop by eating buds of seed sugarcane pieces, apical growing points of young and mature stalks and millable part of the cane. In addition, their burrowing habits lead to damage to the root system leading to the total cane drying. The crop provides good harborage to the rodents, especially if the crop is lodged or not propped unlike in other crops. Even small damage to cane leads to the infestation by insect pests such as termites and diseases such as red rot. Rodent damage, thus, leads to either drying of the cane or deterioration in cane quality through fermentation of cane juice. A study conducted by Sugarcane Breeding Institute, Coimbatore shown that CO 6304, COC 671 and COC 8001 had more rodent damage compared to other varieties. The cane damage was reported to be up to 44% and internode damage was 28%, 1.1.4. Plantation crops Rodents, very often attack Plantation crops such as coconut, cocoa, cardamom oil palm etc. Coconut: A typical rodent damage to tender coconut consists of a small hole of about 5 cm near the perianth region. After gnawing the husk, they consume the inner contents. The damaged nut may fall on the ground in 2-6 days. Rodents often prefer young and tender coconuts. The damage particularly is more in areas with inter-cropping where environment is congenial. Cocoa: The squirrels make damage to the cocoa pods in the centre while the rats cause damage near the peduncle. The intensity of damage to cocoa by rats and squirrels is always at higher side. Cardamom: Rodents make damage to the capsules at the base of the clump. The damage incidence coincides with maturity of crop. Oil palm: Rodents damage oil palm at seedling, flowering and maturity stages of oil palm. The damage will be more for the seedlings and young pods. Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 5 RODENT DAMAGES IN FIELD CROPS AND STORAGE Rat damage paddy (tiller cut at 450) Rodent damage in wheat crop Rodent damage in sugarcane Rodent damage in groundnut Rodent damage in Black gram Rodent damage in cotton Rodent damage in mustard Rodent damage in storage Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 6 RODENT DAMAGES IN HORTICULTURAL CROPS AND POULTRY Rat damage in coconut Rodent damage in cocoa Rodent damage in tomato Rodent damage in pineapple Rodent damage in watermelon Rodent damage in orange Rodent damage in grapes Rodent damage in poultry Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 7 Extent crop loss due to rodent pests, pest species and their distribution in India S.No. Name of the crop Extent of loss (%) Rodent pest species Habitat of species 1. Rice 1.1 to 44.5 Bandicota bengalensis Millardia meltada Mus booduga Rattus nitidus Rattus rattus brunneusculus Irrigated fields Semi irrigated fields Irrigated fields Jhum fields in North east Jhum fields in Mizoram 2. Wheat 2.7 to 21.3 Bandicota bengalensis Millardia meltada Tatera indica Meriones hurrianae Irrigated fields Irrigated dry fields Rain fed fields Desertic soils in Indian desert 3. Sugarcane 2.1 to 31.0 Bandicota bengalensis Nesokia indica Millardia meltada Irrigated fields Irrigated fields in Punjab 4. Groundnut 2.9 to 7.3 Tatera indica Millardia meltada Bandicota bengalensis Irrigated dry fields Irrigated dry fields Irrigated fields 5. Coconut 4.5 to 55.0 Rattus rattus Throughout India 6. Cocoa 30-50 Rattus rattus wroughtoni Funambulus palmarum Funambulus tristriatus South India Andhra Pradesh and Tamil nadu Kerala and Karnataka 7. Oilpalm 11.2 to 57.3 Bandicota bengalensis Hystrix indica Tatera indica Fruits in S. India and Andaman Seedlings in nurseries 8. Vegetables 1.4 to 30.6 Bandicota bengalensis Millardia meltada Tatera indica Meriones hurrianae Funambulus pennanti Irrigated fields Irrigated dry fields Dry fields In Indian desert soils Northern India 9. Fruits Varied Funambulus pennanti Funambulus palmarum Northern India Southern India 9. Storage 2.5 Rattus rattus Mus musculus Residential premises and farm level storage Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 8 II. MORPHOLOGY OF RODENTS  Tail Terminal appendage of the body covered with scales and containing blood vessels; it is used mainly for equilibrium.  Claw Somewhat curved, sharp pointy structure used especially for digging and defense.  Fur Hair covering the entire body, except the nose; its main function is to maintain body temperature.  Nose Middle protuberance of the head with two orifices located above the mouth and having an olfactory and respiratory function.  Vibrissa Long tactile hair located around the nose and mouth used to detect obstacles during nocturnal forays.  Pinna External part of the ear made of cartilaginous lobes that capture sounds.  Digit Terminal end of the limbs formed of various articulated bones bearing a claw and used mainly to feed and move about. STRUCTURE OF TEETH  Incisor Flat, constantly growing tooth with a single root; it is located in the front of the jaw and used for cutting up plants.  Molar Large tooth with several roots; it is located at the back of the jaw behind the premolars and used to grind food. Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 9  Diastema Large space between the incisors and the premolars due to the absence of canines. Dental formula is: I 1-1, C 0-0, P 0-0, M 3-3 Tail  The rat's tail is an extension of the vertebral column  Has a large surface to volume ratio,  Comprises only 5% of the rat's surface area, but it can dissipate about 17% of the rat's body heat  Its length relative to the body  The hairy/ naked (Scaly-number, shape and color)  The presence of terminal hair tuft FUR STRUCTURE  Contour hairs: Bulk of fur, generally colored  Spines: Stiff, generally on back side  Underfur hairs: Short, gives wooly texture  Guard hairs: longer than contours, thick, generally on back Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 16 Habitat: Inhabits irrigated fields, in clear patches and in hedges and grasslands. It is a semi mesic rodent and hence found mostly in semi arid areas. It is associated with T. indica and Mus booduga in Northern India, while in Southern India it occurs in association with Bandicota bengalensis. Habits: It is nocturnal and fossorial with simple burrows. The burrows are small. It thrives upon crop plant parts and grains, which constitute about 63.3 per cent of the total food intake. It has oestrus cycle of 4-5 days and gestation period of 20 days. The litter size is 210 with an average of 6. The annual productivity is 52.5 young ones per female. Pest status: It is comparatively a minor pest. However, it is associated with damage to cotton at sowing and boll stages and in groundnut at pod formation stage. 3.5. Mice Among all rodents, mice are the smaller animals with more resilience and reproductively making them not only as pests, but also as nuisance animals causing damage to non-edible articles due to their nibbling behaviour. House Mice (Mus musculus sp.) Dark house mouse, Mus musculus homourus with whitish under surface is found in the fields as well as in the houses, living in burrows, below rocks and in crevices. It is omnivorous and causes lot of damage to grains and stored food material. They are small rodents (15 g.) with bicolour tail longer than head and body. The dorsum is dark brown to sandy. Distribution: They are pests in all places of the State. Habits: They are nocturnal, fossorial and highly active and have nibbling habit, which result in damage to sacks and foods. Breeds throughout the year with a litter size of 1-8 (Mean 5.6) young ones, oestrous period of 5.7 days, and has a gestation period of 18 days. Young ones reach maturity in 45 days. Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 17 ECONOMICALLY IMPORTANT RODENT PEST SPECIES WITH THEIR HABITAT/ BURROW CHARACTERS Lesser bandicoot (Bandicota bengalensis) B.bengalensis burrows with scooped soil Larger bandicoot (Bandicota indica) B. Indica burrowopen and large Soft furred field rat (Millardia meltada) M. meltada Vertical burrow - without scoop India Field mouse (Mus booduga) M.booduga round circular burrows Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 18 Common Indian Gerbil, Tatera Indica T. indica burrow complexes Desert Gerbil, Meriones hurrianae M. hurrianaeburrows in sand dunes Indian porcupine, Hystrix indica H. indica habitat-crevices and tunnels Non-Burrowing rodents Cocount rat/House rat, Rattus rattus 3-stripped squirrel 5-stripped squirrel Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 19 IV. ZOONOTIC DISEASES SPREAD BY RODENTS In addition to the depredations caused to the agricultural crops and commodities in storage, rodents also transmit various diseases to humans as well as livestock. They serve either as vectors of diseases to man through the direct transfer of disease causing organisms or as reservoirs of diseases which are transmitted to man by arthropod vectors. The frequency of disease transmission is facilitated by the close association, which rodents have with man, living in the houses and consuming and contaminating human food. A proper understanding of their role in transmitting diseases provides means of the prevention of the public health diseases. The rodents transmit bacterial, viral and protozoan diseases 4.1. Bacterial diseases a. Leptospirosis Leptospirosis is a bacterial disease affecting human beings as well as livestock. It is caused by Leptospira interrogans, which are parasitic in rodents and other animals. There are 26 serogroups with about 140 serovars within the species of L. interrogans. This infection is carried by wild vertebrate animals, especially, rodents and transmitted to man. Without laboratory diagnosis of leptospiral infection, this disease cannot be diagnosed with certainty. Therefore, Leptospirosis is a hidden disease officially not documented in number of states since scanty diagnostic facilities are available. It is reported as endemic in the States of Kerala, Karnataka, Gujarat, Tamil Nadu, Maharashtra and UT of Andamans and Nicobar. However, reports exist from several other states, viz., Orissa, Madhra Pradesh, Delhi UT, Andhra Pradesh etc. The clinical features may resemble those of fever, influenza, typhoid fever, dengue hemorrhagic fever, viral hepatitis, bacterial meningitis or acute renal failure. Illness lasts from few days to 3 weeks with low human mortality Pathogenic leptospires survive for long periods in the convoluted tubules of the kidney in natural hosts, multiply and are shed in the urine up to 100 million leptospires per 1 ml. of urine. They survive in moist warm soil and stagnant waters, particularly if the pH is on the alkaline side. Wild and domestic rodents, carnivores (jackals, dogs), herbivores (cattle, sheep, goats), pigs, hares, frogs and humans are infected by contact with soil or water contaminated with these organisms. Therefore, the disease is common among rice and sugarcane field workers/farmers, fishermen and sewer workers and is considered as occupational hazard. The limited work in India so far indicated only three rodent species i.e., Rattus norvegicus, Rattus rattus and Bandicota bengalensis, as important shedders or vectors of Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 20 the leptospirosis. The disease is more common than ordinarily diagnosed and many socalled fevers of unknown origin are due to it. Further, the denser the rodent populations, greater will be the risk of infection to man. As leptospirosis results from contact of skin or mucosa with urine contaminated water, general measures of prevention such as rodent control, disinfection of water and the wearing of protective clothing contribute to its prevention. Since parts of Tamil Nadu are endemic, potential threat to human health exists. In view of this WHO initiated a project and included 2 districts of Tamil Nadu for preventive actions of this disease. b. Plague Recently in late 2004 incidence of plague in Uttaranchal was noticed by NICD. Definite records of plague incidence in India exist from 1896 onwards with rodents as vectors/reservoirs for this bacterial disease. Rodents are primary hosts of the causative bacteria, Yersinia pestis, for the plague disease through oriental flea, Xenopsylla cheopis. In India the sylvatic plague foci are recognized in the foothills of the Himalayas (Jammu and Kashmir, Himachal Pradesh, Uttaranchal, Uttar Pradesh, and Bihar), in the watersheds of the Vindhyas (Madhya Pradesh) and in the Deccan Plateau (Maharashtra, Karnataka, Andhra Pradesh, and Tamil Nadu). Recent report is from Uttaranchal during 2004. Among rodents, some species are susceptible to the disease leading to high mortality, while others are relatively tolerant to the disease. The Indian gerbil, Tatera indica is resistant to the disease and as such act as permanent reservoir host in many foci in India. The T. indica lives in wild and away from human habitations. However, summer periods or prolonged dry spells compel them to go near the fields around human habitations. During this period the commensal rodent species like the Lesser bandicoot, Bandicota bengalensis in these fields will get infested with the plague-infected flea, Xenopsylla cheopis. When this species interacts in the domestic areas the infected flea will reach the House rat, Rattus rattus. Both R. rattus and B. bengalensis are susceptible to infection, disease, and rapid mortality; they act as links between wild rodent infection and human plague. Sick and dying rodents may fall of from roofs or on the ground. As the body temperature of these carcasses fall, fleas escape and find other warm-blooded hosts such as dogs and humans around the vicinity. . c. Salmonellosis Salmonellosis caused by Salmonella bacillus is characterised by acute gastroenteritis in man. Contaminated water and foodstuffs do the transmission by faeces of an infected person or animal, and rodents are very frequently a source of such infection. Although rats Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 21 are not the only animal source of salmonellosis infection, worldwide information on this disease indicated them as one of the major sources. 4.2. Viral infections Although viral infections are reported to be highly prevalent in Asian countries, India has no reported vectors for transmitting the hemorrhagic fevers caused by arbo and arena virus. The virus of Kyasanur forest disease is widely distributed in India with human infections only in Karnataka State. Transmission is by Haemaphysalis ticks and the disease is maintained in small mammals, such as Suncus murinus and Rattus species, while monkeys in forest areas serve as amplifying hosts. 4.3 Rickettsial infections There are five diseases in this group of zoonoses caused by rickettsia and all have rodents implicated, at least in part, as reservoir hosts. Among them, Murine typhus is a very widespread, acute, febrile rickettsial disease caused by Rickettsia typhi. The reservoir hosts of the disease are primarily Rattus spp., Rattus norvegicus and R. rattus. Through fleas, which are vectors from rat to rat or from rat to man. The most important flea vector is Xenopsylla cheopis. This disease is most common in cities with high rat populations and a relatively high incidence of the vector flea. Due to the difficulty in its diagnosis the disease is under reported in tropical areas where it may be confused with a number of other febrile diseases. 4.4. Helminth and Protozoan diseases Leishmaniasis is caused by protozoan parasites belonging to the genus Leishmania. Cutaneous leishmaniasis caused by Leishmania tropica is very widespread. The cutaneous ulcers of varying degrees of severity are common in areas where sand fly vector, Phlebotomus species are not controlled. Visceral leishmaniasis is caused by Leishmania donovani and widely known as kala azar. The vector is Phlebotomus sandflies. The reservoirs include man himself as well as dogs, other canines and a number of wild rodent species. The exact role that rodents play as reservoirs of the disease is not clear. Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 22 V. ECOLOGY AND ETHOLOGY OF RODENTS Understanding of rodent behaviour is a vital for planning eradication of longestablished rat populations in agricultural as well urban ecosystem. They have many ecological and behavioural adaptations which are given below: Habitat They adapt to a wide range of habitats. Bandicoots are fossorial (live inside the burrow) they are good diggers. The borrows will be occur only in irrigated croplands the burrows having a scooped soil at the entrance with pebbles. Major channels and around village gardens are prime habitats during fallow. The squirrels are arboreal. They live in tree trunks and make nest. House rat in urban areas they are found around warehouses residential, buildings, and other human settlements. In cities their preferred habitats are in dry upper levels of buildings, so they are commonly found in hollow places in wall cavities and false ceilings. In the wild conditions they live in cliffs, rocks, the ground, and trees. R. rattus are excellent climbers and found in trees, such as pines and palm trees. Their nests are typically spherical and made of shredded material, including sticks, leaves, other vegetation, and cloth. The Norway rat lives in the underground. It is strong burrowing animal sometime the burrowing activity may lead to collapse the building. Porcupine make shelters in caves, rock crevices, dark holes, or dens / burrows, excavated by the species along the side of a hill / hillock or in the plains. The burrows are usually self constructed and extensive with a long entrance tunnel, multiple exits and large inner chamber. It is essential to understand the spatial distribution of rats and their burrow for management of rodent populations. For example, in Indonesia, monthly trapping of rodents in 5 different habitats indicated that village gardens and the banks of main canals were important breeding habitats (source habitats) for rats. Rat campaigns conducted the week after the rice crops are transplanted are directed at these two habitats. This is when rats aggregate into these habitats following the disturbance of cropping lands during land preparation and planting of the rice crop and before the rats begin breeding. Food Habit Rodents like to live near water of any sort, and prefer foods rich in carbohydrates and protein. Rodents are omnivorous and can eat a wide range of plant and animal foods. Fruits, seeds and invertebrates are also included as a major portion in the diet. Larger bandicoot main food items are Invertebrates particularly insect larval, arthropods, reptiles, birds, and cockroaches. Unlike mice, rats cannot survive without open water requiring about Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 23 an ounce of water daily. The physical capabilities of rats are extremely alarming. They can climb stairways, pipes, wires and even bare walls with a rough surface. Most rat populations are nocturnal operating between dusk and dawn. They will adjust, however, to feed during times which food is the freshest or most available. FOSSORIALITY Generally rodents live in fossorial (live under the ground) but in Indoors, rats prefer to nest on ground levels, though they will move to upper levels and attics when populations are large enough. Squirrels live in arboreal habitats, live in tree holes/cracks and crevices. Nests may be located in wall voids, underneath floors, in crawl spaces, underneath and behind stationary equipment, and in stored pallets or piles. These rats have even been found nesting within furniture in rooms which the occupants frequent. Outdoors, nests are often burrows located around the foundation of the structure. These burrows will become expanded and enlarged as the rat population grows. Many burrows may interconnect with one another forming a complex network of underground tunnels. These burrows will contain one main entrance, as well as two bolt holes which are used for escape purposes. Constant environmental conditions will be maintained inside the burrows, facilitated by soil. The depth normally depends on the atmospheric temperature • Porcupines – make crevices between rocky areas; the crevices are normally tapering; complex of crevices due to gregarious living. • Bandicoots – scooped soil exists before the burrows with soil pebbles. • Soft furred field rat – vertical burrow, which extends laterally • Gerbils – the burrow is complex in nature NOCTURNALITY They are crepuscular (Active mostly after dark), but are adaptable if warranted by circumstances; indoor mice are generally nocturnal but less predictable than rats. The spontaneous activity starts at evening hours after sunset and have exploration, feeding and feeding rhythms; the activity will be minimize by 9.30 pm. Again they become active in early morning having exploratory and feeding activities. EXPLORATION Rodents have a habit of checking the environment during the spontaneous activity period. This is to guard the area where they live to check any incursions or change in the environment. This is an in born instinct of all rodents. Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 24 THEIGMOTAXIS Prefer to travel along, and in contact with, vertical surfaces rather than in the open; wary of crossing open spaces that provide no cover. In field conditions they prepare to move side of the bund. Hence, the baits placed on the bund are not accepted. Territories of most of the rodents ranging from 50 to 150 feet from the burrow, however, rats will travel up to 300 feet to a food source. As rat populations grow, competition, conflict, and fighting begin to increase. Large males will become dominant and any given territory can be divided up into several social orders where subordinate males also maintain an smaller area. Many rats will often be seen during the day, as they must feed when larger dominant rats are inactive. AGONISTIC BEHAVIOR Agonistic behavior refers to the complex of aggression, appeasement and avoidance behavior that occurs between members of the same species. Agonistic behavior is a much broader term than "aggression," which refers to behavior patterns which serve to intimidate or damage another (for more, see McFarland, 1982). SOCIAL AGONISTIC BEHAVIOR Agonistic behavior involves several actions, or motor patterns, including chasing, sidling, boxing, biting, and kicking, as well as audible and ultrasonic vocalizations. Agonistic behavior can occur between rats in a colony, and between resident rats and intruders. Urine Marking Urine marking in rats refers to the deposit of drops or smears of urine in the environment, sometimes accompanied by secretions from preputial sebaceous glands (Birke 1978). Urine marking is a type of scent marking, a form of chemical communication, in which one rat, the sender, generates a chemical signal (the drop of urine) and transmits the signal by depositing the drop in the environment. Another rat, the receiver, identifies, integrates and responds (either behaviorally or physiologically) to the signal. It is assumed that the sender-receiver relationship is the result of natural selection, such that the sender's signal produces a response in the receiver that benefits the sender in some way (e.g. the signal attracts a mate for the sender etc.), while the receiver assesses the signal and responds in a way that most benefits the receiver (Agosta 1992). Urine marking is very common in mammals, and it has become adapted for use in a variety of contexts and may have more than one function in any given species. In addition, it may have different functions in different species (Johnson 1973). Chemical secretions contain an enormous amount of information (Agosta 1992). A rat who smells a urine mark can determine all sorts Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 25 of things about the rat that produced it: its species, sex (Brown 1977), age (juvenile vs. adult), reproductive status (Carr and Caul 1962), familiarity (Krames and Shaw 1973), social status (Krames et al. 1969), individual identity (Brown 1988, Carr et al. 1970), and current stress level (Mackay-Sim 1980, Giesecke 1997, Valenta and Rigby 1968). In addition, rats can tell how long in the past a urine mark was deposited. NEOPHOBIA Rats constantly explore their territories and are very wary of new foods, new objects, or changes in their environment. This behavior is known as neophobia and can last up to several weeks. This has definite impacts on the Control of Norway Rats. They exhibit bait shyness , often not returning to food which makes them sick after taking little nibbles in initial tasting. These are extreme neophobic rats which avoid all baits and traps. The neophobic response can be one of the most pertinent obstacles to efficient rat control (Lund 1988). Barnett (1958) defined neophobia as the avoidance of an unfamiliar object in a familiar place. It causes problems in poisoning programmes because neophobic animals will avoid new foods and even foods previously eaten if they are placed on or in a novel object (Barnett 1988). The response varies not only between species (see below) but also between populations of the same species (Mitchell et al. 1977) and between individual animals (Cowan & Barnett 1975). Neophobic periods: R. rattus – 3 days B. bengalensis – 1 day M. meltada – 5 days T. Indica – 3 days BAIT SHYNESS Aversion towards the poison bait is called bait shyness. A number of researchers, especially in India, have looked at the role of various food characteristics in the development of conditioned food aversions, and aversions to different poisons (e.g. Howard et al. 1968; Bhardwaj & Khan 1978; 1979a, b; 1980; Rao et al. 1980). Thomas & Taylor (2002) noted that either bait shyness or poison resistance was apparent in the rat population on Ulva Island. Cowan et al. (1994) recommended micro-encapsulation of poisons as a way of reducing the formation of learned aversions, by delaying the symptoms of poisoning. Sub lethal doses of acute rodenticide will not kill the rodents, but the minute quantities of phosphine generated in stomach will give stomach disturbance. Rodents will associate this discomfiture with bait material ate. Consequently they avoid eating the food itemBait Shyness. It is temporary phenomenon. Persistent periods: R. rattus – 75 days Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 32 Erratic results have been reported while using this rodenticide. Further, the bait material carrying this rodenticide should not contain more than 10% protein; otherwise it sill reduce the efficacy. These limitations made this rodenticide ineffective. In case of accidental ingestion, nausea, vomiting, diarrhoea, abdominal plain, paresthesias, profound muscle weakness, trembling, faintness, paralysis of arms and legs, hypokalemia leading to ECG abnormalities and dysrrhythmias, acute renal failure and pulmonary dysfunction. Death may result from hypokalemia, dysrrhythmias, cardiac and respiratory failure. 7.2. SLOW ACTING RODENTICIDES As on now the slow acting rodenticides are all belonging to the category of anticoagulants, which act primarily, preventing the blood coagulation. The earlier anticoagulants, which have been introduced in the initial years, are first generation anticoagulants. However, with the advent of resistance among the residual populations, anticoagulants that are more potent have been developed. These are called second generation anticoagulants with added advantage of effective kill of even resistant populations with reduced quantify of poison baits. 1. Warfarin Warfarin belongs to the first generation anticoagulant category and kills rodents after uptake of 4-5 daily doses of 0.2 mg/kg per day. Its acute toxicity is 173 mg/kg. It was extensively used for controlling rodents in storage. It is recommended at 0.025% a.i. in cereal baits and in liquid bait. However, warfarin is not available in market at present. 2. Coumafuryl It is also a first generation anticoagulant, is stable, and persists in baits. It has a high toxicity for dogs and pigs. Its acute oral toxicity is 900-1200 mg/kg. for rats, but repeated administration for 14-21 days at a rate of 0.1 to 1 mg/kg. It gives considerable control success due to anticoagulant mode of action. It is recommended at 0.025% a.i. in solid baits. However, it is used in limited level in India. It is not available in the market. 3. Coumatetralyl Coumatetralyl is an improved first generation anticoagulant and is a bluish amorphous powder. In market, it is available in 0.75% a.i. concentration. The acute toxicity is 16.5 mg/kg., while the chronic toxicity LD 50 for rats is 0.3 mg/kg. daily for five days. Hence, it is recommended in 'saturated baiting' technique with alternate day replenishing. It is formulated as tracking powder (0.75 per cent) and as ready-to-use bait (0.0375 per cent). It is recommended at 0.0375 per cent a.i. in solid bait for controlling rodents in storage situations. It is now not available in the market. Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 33 4. Bromadiolone Bromadiolone is a second-generation anticoagulant and kills the resistant rodents. The acute oral toxicity is 3-5 mg/kg. It has no chronic toxicity. Single feeding of the baits also brings mortality of rodent population (40-60%) three days after the application. Hence, it is recommended in 'Pulsed baiting' technique. It is formulated as concentrate powder (0.25 per cent) and as ready-to-use bait (0.005 per cent). It is recommended at 0.005 per cent a.i. in solid bait by mixing 1 part of the concentrate in 49 parts of bait mataerial for controlling rodents in storage and agricultural situations. Application in 10 paper packets gave significant results in field conditions. Under domestic situation usage in simple bait stations yielded good results. The ready-to-use cake is coated with thin layer of wax to protect the bait from weather. These cakes are recommended to use in in-accessible situations in field conditions. 7.3. Respiratory poisons Aluminium phosphide 0.6 g. pellets are recommended for rodent burrow fumigation @ 2 pellets per burrow. This is a restricted rodenticide to be used under the supervision of technically competent persons. The pellets can be procured by the Government Departments directly from the manufacturers. The burrows of B. bengalensis can be effectively treated with this fumigant. One pellet per burrow will be effective to control field mice. The pellets release phosphine gas in the atmospheric conditions, which is lethal to the rodents inside the burrows. Due to this care is required to be taken to insert the pellets deep inside the rodent burrows and burrows are to be plugged to prevent leakage of the toxicant gas from the rodent burrows. Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 34 VI. INTEGRATED RODENT MANAGEMENT Integrated pest management is a system which in the context of the associated environment and the population dynamics of the pest species, utilises all suitable techniques and methods in a compatible way and maintains pest populations at levels below the economic injury level. Rodent control is a problem of applied ecology and the control measures should be based on proper translation of ecological factors into management polity. The primary aim is to reduce damage, rather than to kill the pest. However, most often this is achieved by use of a lethal chemical. However, if lethal control is followed by rapid immigration then the damage reduction may be short lived. Thus it is important to take account of spatial dynamics of the pest. Simple ecological theory treats a population as a group of organisms in one place at one time, the number of which change through time according to the number of births, deaths, immigrants and emigrants. Although rodents have potentiality for fast breeding, the geometrical progression is countered by various limiting factors operated by nature. Implantation failure, intra uterine mortality, maternal cannibalism and postnatal mortality due to social strife etc. limit their number. However, the higher carrying capacity of crop fields result in maintaining more number of rodents resulting in significant crop losses. Different methods exist in controlling rodents. However, each method has its own limitation. The methods that are in vogue and limiting factors are given below: Environmental and cultural methods Several of the agronomical measures like deep ploughing, bund trimming and other land preparation measures to raise the crops reduce the carrying capacity of the habitat for rodents. Weed removal as a routine practice by the farmers in the crops also deprives harbourage and alternate food for the rodents. Sharma and Rao (1989) reported reduction in bund dimensions, viz., height and width resulted in decline in rodent infestation in rice fields. Alley planting in rice also reduces the rodent damage (Anon, 1959-69). Physical elimination of the field rats is in vogue by certain communities in parts of the country. Irulas of Tamil Nadu, Erukulas of Andhra Pradesh belong to this category using rats for food purpose. Sometimes, they employ fumigation by Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 35 indigenous method by smoking haystack in to their burrows. However, often the physical killing is done around ripening of the crop after the crop gets maximum rat damage. An improvised smoke generator (burrow fumigator) was developed by Acharya N.G. Ranga Agricultural University, Hyderabad for effective control of burrowing rodents. It involves burning of farm wastes like paddy straw leading to generation of smoke, which is pushed into the burrow tunnel with the help of blower (Rana and Tripathi, 1999). Physical methods Trap Barrier System (TBS) is being tried in different countries employing fences to the rice farming and fixing traps at different intervals. Trap crop is also is added to attract rats to immigrate by growing a small patch of the crop on the periphery. However, looking at the cost of fencing and land holdings, it may not be appropriate in Indian conditions to use this method, although the preliminary studies yielded significant results. However, in North-eastern States this method can be followed in jhum cultivation. Non lethal electric fencing as a barrier method were found to be cost effective and has limited extension value. Trapping Trapping is one of the oldest methods of animal control. A variety of traps can be used against rodentslive or snap. The efficacy of trapping, whether live or snap trap, depends on operational conditions of the trap, number of traps set, type of bait, place and time of placement. Scientific literature has seldom proved trapping as effective method against rodents as a measure of reducing their numbers. However, they can be employed in controlling localized infestations effectively. Tanjor kitties, bamboo Palmyra traps are highly effective for localized infestations. They help in maintaining rodent numbers at a low level once they have been reduced by other methods. Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 36 Use of rodenticides Generally rodenticides are used for mass scale rodent control campaigns. Application of rodenticides and environmental manipulation should be considered as complimentary to each other rather than alternative approaches. Amalgamating various methods as above results in reduction in rodent damage in different situations. Role of predators Snakes and owls have been the natural predators for field rodents. Bird perches are used for attracting owl perching in the nights to facilitate hunting the colonising rats. The perches should be used at tillering stage of the crops to tackling immigrating rodents. However, if these perches are continued in later stages, granivorous birds may cause damage to the panicles. Since most of the predators of rodents are general feeders, they often tend to feed on food other than rodents. Cats in residential premises are one of the examples. Declined rodent population after harvest of the crops also makes the predators to leave the area. There is also sometimes a possibility of predation triggering increase in rodent populations after partial removal of the rodents. Attempts were also made with parasites and pathogens to bring successful rodent control. However, the efforts are so far not fruitful since they also equally affect human populations. Attempts are in progress to use immuno contraception through viral vectors (VVIC) among rodents. However, the trials are at infancy stage only. Ultrasound and electromagnetic devices The sense of hearing among rodents is above 20kHz thus extending well into ultrasonic range. Ultrasound devices are being used as deterrents to rodent immigration. However no convincing evidence was found them as effective against rodents. Similarly little scientific support was found for use of electromagnetic devices. Chemical repellents There is no effective chemical repellent available that is not also toxic. Although pheromones appear to be promising, lot of scientific work is required to identify, isolate and bring out the pheromones for extension purpose. Botanical based repellents are also available under different trade names (EcodonR -Castor based repellent, Bio-repel etc.) for use as field/ bund sprays Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 37 8.1. Suggested control measures in field conditions: Day 1: Make a survey in the area to locate rodent burrows on the bunds and no mans lands around the fields. Identify the live rodent burrows, through the presence of soil plugs and faecal pellets. For using acute rodenticide like zinc phosphide keep pre bait of approximately 20 g. broken grain of staple food with little amount of vegetable oil. (Or) Prepare poison bait of Bromadiolone at 0.005% a.i. in cereal base. Keep the bait approximately 15 g. wrapped in paper packet inside the burrows. Day 4: Prepare zinc phosphide poison bait at 2.5% using broken grain of staple food with vegetable oil as binding medium. Keep bait deep in the burrows. Day 5: Close all rodent burrows. Locate dead rodents and bury them. Normally most of the rodents die inside the burrows. Hence, mostly dead rodents cannot be seen. Day 6: Treat the residual burrows with anticoagulant like Bromadiolone based on the situation. Place 1 piece of Bromadiolone wax block (16.6 g.) or 15-20 g. of loose Bromadiolone bait (0.005% a.i. Bromadiolone mixed in bait material) in packets in all the reopened burrows. With Bromadiolone, rodents die between 3-10 days after the placement of bait material. In rodent endemic areas or when the rodent problem is quite serious, fumigant like Aluminium phosphide can be used to treat all the residual rodent burrows in the field conditions. The residual burrows are the reopened burrows after closure of the burrow entrances with mud one day prior to the observations.  Cover the nose and mouth with a cotton cloth.  Cover hands with gloves/polythene cover.  Take a tube/pipe.  Take two Aluminium phosphide pellets.  Insert the tube deep inside the rodent burrow. Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 38  Leave the Aluminium phosphide pellets inside the tube.  Remove the tube/pipe and close the burrow. Fumigation should be done under the technical guidance and strict supervision of officials from the State Department of Agriculture. Stages in community rodent control campaings using rodenticide poison baits Identifcation of live rodent burrows Prepartion of rodenticide poison bait Packeting of poison bait Pocketing of poison bait packets Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 39 IX. RODENT INFESTATION MEASURMENT - PROTOCOLS 1. RODENT INFESTATION MEASUREMENT A. Burrow count method: In agricultural land and open fields freshly opened burrows are counted for population estimations. Some species can also be identified based on their burrowing characteristics. 1. Live burrow index 2. Plug all burrows in the evening hours. 3. Next morning observe and count reopened burrows per unit area (called as live/active burrows) Burrow index: 0-25/ha : low 25-50/ha: moderate 50 above: high B. Capture Mark Release (Cmr) Method: Lincoln Index ➢ Approximately 54 traps ( 120x75m area) are set in a grid pattern at 15m apart ➢ grids to be replicated by three in each habitat ➢ unset traps laid for few days for acclimation/ avoid neophobia/shyness ➢ traps are pre baited for 2-3 days ➢ traps are set in the area for 24 hrs ➢ captured rodents are marked by toe clipping and released ➢ second trapping could be after 1-2 weeks for 24 hrs. ➢ second trapping would included capture of old ( marked) rodents also ➢ size of population can be calculated as; FORMULA : RT = R1 X R2 RM Where: R1 = no. Of rats caught first time, marked and released R2 = no. Of rats caught 2nd time including marked & unmarked RM = no. Of marked rats caught 2nd time RTt = total rat population Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 40 C. Removal Method ➢ Based on removal/kill trapping ➢ Traps are set in checker board fashion/ or in lines ➢ Trap-trap distance may vary (5-15m) depending on the species ➢ Trapping is continued for 72 hrs. ➢ Traps checked at 4-6 hrs interval. ➢ Trapped rodents are removed ; traps reset by replenishing the bait. ➢ Trapping blocks should be replicated at least by 3 in every habitat. ➢ Relative density/ha will be number of rodents collected. ➢ If an accurate number is desired trapping may be continued till there is no catch. Trap index (rodents/day/trap) calculated by following formula FORMULA : I = M N x t Where; N = number of traps used, t = trap nights, M= total no. Of rodents trapped 2. RODENT DAMAGE ASSESSMENT Rodent damage assessment in rice Diagonal method: Select a field at random. Select a plot at random. Select a diagonal. Start with first hill. Count cut and uncut tillers. Select next position on the diagonal. Repeat step 5 and 6 until 25 samples at equidistance are taken. Calculate damage incidence (P). P = ( A x 100 ) / ( A + B ) Where A = Total no. of damaged tillers in the 25 hill sample and B = Total no. of healthy tillers in 25 hill sample. Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 41 Rodent damage assessment in wheat 1. Select field at random and also plots at random 2. Select first position of sample frame on one of the diagonals 3. Place sample frame on the ground without looking. 4. Count cut and uncut tillers and note on record sheet. 5. Select next position of sample frame by walking 3-5 steps. 6. Repeat last two steps till ten samples are taken. % Damage = No of cut tillers x 100/ Total no of tillers in a sample Damage assessment in Coconut: Random assessment of rodent damage to coconuts can be done in the following way: Step 1. Identify one block of the plantation with approximately 100-150 trees Step 2. Survey these trees to find out number of trees with fresh rodent damaged nuts fallen at the bases Rodent No of trees with damage Infested --------------------------- X 100 Trees (RI) Total No. of trees For damage intensity among the infested trees following procedure may be adopted: Step 1 Randomly select 10 trees with the nut falls. Step 2 Take observations on all the selected trees on total number of nuts and damaged nuts covering all bunches. Step 3 Calculate the mean nut damage (MND) per tree (%) Coconut Damage (%) = RI X MND Damage assessment in sugarcane 1. Select plot at random at least 25 meters long with 25 rows. 2. Count total rows and divide by ten to get number of rows to be sampled. 3. Select randomly at spot on the first row. Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 48 3. How it is applied Loose(2)/Packed (3)/Bait stations (4) 4. Place of application Field bunds (1) / Rat holes (3) / Bait stations (4) 5. Time of application Morning (1) / Mid day (1) / Evening (4) / Night (1) 6. Dead rats are thrown out (1) / Buried (4) 7. Rats in traps are released out side (1) / killed (4) 8. Safety precautions taken (4) / not taken (1) 9. Poison obtained from others (2) / purchased (4) ------------------------------------------------------------------------------------------------------------ Analysis of survey result: Score obtained for knowledge: Total score for knowledge : 40 Percentage of the score : Level of knowledge : Low/Moderate/High Score obtained for practice: Total score for practices : 36 Percentage of the score : Level of practices : Low/Moderate/High Score obtained for Attitudes : Total score for Attitudes : 32 Percentage of the score : Social Category : Innovator/Primary adoptor/Secondaryadoptor/Laggard Levels of Knowledge and Practices based on score: Score below 50% : Low Score above 50%, upto 80% : Moderate Score more than 80%. : High Adoption category based on score of Attitudes and suggested motivational media: Score (%) Category Motivational media Score above 90 of attitudes : Innovators Media and Publicity Score from 80 to 90 : Primary Adoptors Training programmes Score from 40 to 80 : Secondary Adoptors Demonstrations/Farmers’ interactions Score less than 40 : Laggards Meetings and interactions Signature Training Manual on IRPM: Dr N Srinivasa Rao, Dr AMKM Rao, Dr PV Satyanarayana and B Anusha Page 49 Suggested Readings Alfred, J.R.B., Sinha, N.K. & Chakraborty, S. 2002 Checklist of mammals of India. ZSI, Calcutta, 171-225 Ellerman, J.R. 1961 The fauna of India including Pakistan, Burma and Ceylon. Mammalia Volume 3. ZSI, Calcutta, 1-866 Neelanarayanan, P and Kanakasabai, R 2000 Rodent pest management – A traditional approach. Pestology 24: 12-19. Prater, S.H. 1971 The book of Indian animals. BNHS, Bombay, 193-217 Rao, A.M.K.M. 2003. Rodent problems in India and strategies for their management. In: Rats, mice and people: rodent biology and management (Eds. Singleton, GR, Hinds, L.A, Krebs, C.J and Spratt, D.M), ACIAR Monograph No 96, Canberra, 203-212. Srinivasa Rao, N and M. Nanda Kishore. 2009. Seasonal changes in the population size and reproduction of Bandicota bengalensis in rice-rice-pulse ecosystem in A.P. Indian Journal of Plant Protection 37(1&2): 59-63. Srinivasa Rao, N and M. Nanda Kishore. 2010. Evaluation of Trap Barrier system for the management of lesser bandicoot rat, Bandicota bengalensis in irrigated rice. Indian Journal of Plant Protection 38 (2): 193-196. Srinivasa Rao, N and M. Nandakishore. 2013. Baiting through PVC pipe bait stations –A low cost baiting technique for rodent control in rice. Annals of Plant Protection Sciences 21 (1): 167-171.