Everything you need to learn about controlling pests at home. Learn about how to control: 1. House Fly 2. Mosquitoes 3. Sand Flies 4. Cockroaches 5. House Crickets 6. Bed Bug 7. Human Louse 8. Rat Flea 9. Black Ants 10. Wasps 11. Book Louse 12. Silverfish 13. Greater Wax Moth.
1. House Fly, Musca Nebulo Wiedemann (Diptera: Muscidae):
The house fly is distributed all the world over and it assumes alarming proportions in hot and humid climates. In India, the common housefly belongs to two main species, Musca vicina and M. nebulo, the latter being more common. M. domestica Linnaeus occurs only in the temperate climate obtained in the Himalayas and other places.
Of all the familiar household pests, the house fly is the commonest and is found wherever there is human habitation and wherever unhygenic conditions prevail. It is not only a nuisance, but it assumes prodigious importance in transmitting micro-organisms of certain infectious diseases notably diarrhoea, dysentery, cholera, typhoid and other enteric fevers.
It is one of the four F’s in the epidemiology of these infectious diseases; faeces, fingers, flies and food. It also serves as an intermediate host for Helminthes, of which 3 species of tape worms are parasitic on poultry and 3 species of nematodes are parasitic on horses, mules and donkeys.
The adult house fly, about 6-7 mm in length, 13-15 mm across the wings, has a dull colour, pale grey wings, with a yellow base, greyish dorsum of the thorax, with 4 equally broad longitudinal lines and a plumose arista on the antenna.
Life-Cycle:
The life-cycle of a fly, under favourable conditions of hot and moist weather, may take only 12-14 days from the egg to the adult stage. However, in colder weather, this cycle is prolonged. Copulation takes place 24 hours after emergence and the females lay 15-150 small, white, elongate eggs in batches in heaps of manure, faeces or any other type of filth.
Each female lays about 500 eggs and the incubation period varies from 12 hours to 12 days, depending upon the season. The larvae or maggots, as they are commonly called, crawl to the margins of the breeding material and pupate in brown, barrel-shaped puparia for 4-5 days. The adult flies live for 20-30 days and there are 10-12 generations in one summer.
Damage:
The greatest damage done by flies is the contamination of food, resulting in the transmission of important infectious diseases to human beings and in the transmission of parasitic diseases to certain mammals and birds of agricultural importance.
Control:
(i) The population of house flies can be kept suppressed by the proper disposal of manures, garbage, sewage, food waste, human excrement, dead animals and other organic materials,
(ii) Inside the houses, spraying the flies with malathion / diazinon 2 per cent or trichlorphon 0.5 per cent is effective in killing them. The deposits of the sprays left on the walls also continue to be effective.
(iii) Poison baits and sticky paper strips attract and kill a large number of flies.
(iv) Fly-swatters should always be handy to knock off and kill the flies,
(v) The surfaces of windows and doors where the flies rest, may be smeared with 3 per cent malathion or 1.5 per cent diazinon emulsion with the help of a paint-brush.
2. Mosquitoes:
Mosquitoes belong to the sub-order Nematocera of the order Diptera and all the 2,500 species described in the world so far, belong to the family Culicidae. Mosquitoes inhabit almost all parts of the world except the Polar Regions. These insects are small and delicate having 3-6 mm their body length, although some species like Psorophom ciliata (Fabricius) and Psorophora howardii may measure as much as 9 mm in length having a wing span of 13 mm.
They inhabit up to 4,200 metres altitudes in Kashmir and 1020 metres below the sea level in gold mines of South India. Their egg, larval and pupal stages are spent in water and, therefore, the presence of water in the environment is essential for their breeding and existence. They commonly breed in marshy lands, near filthy stagnant ponds, cesspools, dump cellars and standing rain or canal waters.
The mosquitoes are among the most unwelcome biting pests because they cause irritation and itching. It is the female that gives bites. Mosquitoes as a group, transmit, in human being malaria (protozoan pathogen), Bancroftian and Malayan filariasis (nematode infection), and the arboviruses namely, the yellow fever virus, the breakbone or dengue haemorrhagic fever (DHF) and the dengue shock syndrome (DSS) viruses, the Chikungunya virus, Japanese encephalitis virus, the West Nile fever virus, etc.
The species of mosquitoes which are of importance in medical entomology are those belonging to the genera Anopheles, Culex and Aedes. The various species of Anopheles transmit the malarial parasite, Plasmodium spp. from man to man. Culex quinquefasciatus say is the principle intermediate host of Wuchereria bancrofti and spreads filaria in urban areas, while Mansonia spp. are the intermediate hosts of Brugia malayi and spread filaria in rural areas. Aedes spp. are responsible for the transmission of the dengue fever, various types of encephalitis and the yellow fever.
A. Genus-Aedes:
The genus Aedes has many species but among them, four species are very important. These are Aedes aegypti (Linnaeus), Aedes albopictus (Skuse), Aedes vittatus (Bigot) and Aedes variegatus.
A. aegypti, originally an African species, was introduced in India in the beginning of the nineteenth century. This is also called the tiger mosquito as it has silvery white stripes and bands on a nearly black background. The broad, flat, imbricated scales completely cover the head and abdomen, which are also present on the scutellum.
The scales, thus, give a characteristic satiny appearance. It can be easily spotted by the lyre-shaped white marking over the dorsum of the thorax. It is purely domestic mosquito, rarely found far away from towns or villages. Like other bright coloured mosquitoes, it bites chiefly during the day and only occasionally at night. A. aegypti breeds in association with A. stepliensi and C. quinquefasciatus in domestic and peridomestic habitats.
The pH of its aquatic habitat generally varies from 7.3 to 8.4 with an average of 7.4. Females can live for a maximum period of 225 days with a mean longevity of 70-116 days. Each female deposit from 20 to 75 eggs at a time. The number of eggs in one genotrophic cycle laid in one, two or more layings averages about 140. The total number of eggs laid by a single female may be 752 in as many as 16 layings within 72 days.
The eggs may be deposited along the sides of the container above the water surface, where they are closely attached. At places, eggs can be seen floating on the water surface separately, instead of being cemented together to form rafts as in Culex mosquitoes.
The eggs are very minute, black, cigar-shaped and extremely resistant to desiccation owing to the presence of highly chitinised shell. The eggs can survive without water at least for one year. They are generally found in cisterns, rain water barrels, unused tins, earthenware pots and other small artificial water collections.
The egg stage lasts 2 days whereas the larvae complete their development within 4-9 days and the pupal stage lasts 1-5 days. The larvae are bottom feeders and can dive as deep as 1.5 metres in water. The larval head and thorax are broad and they appear strong and stout. The larvae have a characteristic worm like movement.
There are lateral chitinous hooks, one pair on each side of thorax. As many as 8-10 scales are arranged in a row on the lateral aspects of 8th abdominal segment. The siphon tube is short and stumpy. Adult A. aegypti mosquitoes attack from behind or under tables or desks, its sound is not quite audible. It has the habit of hiding itself behind pictures or furniture.
B. Genus-Culex:
This is a domestic mosquito, bites human beings and thus causes irritating lesions. Certain species also transmit filaria, Japanese encephalitis, yellow fever and dengue fever. Culex pipiens Linnaeus is cosmopolitan in its distribution. It has several varieties including Culex pipiens fatigans Wiedemann (now called C. quinquefasciatus), C. pipiens pipiens Linnaeus and C. pipiens molestus. The former two varieties can be differentiated on the basis of their male genitalia.
The most common mosquito from this complex in our country is represented by C. quinquefasciatus. The other important species occurring in India include C. vishnui Theobald, C. pseudovishnui Colless, C. tritaeniorhynchus, C. bitaenioryhynchus Giles, C. sinensis, C. gelid us Theobald, C. sitiens Wiedemann, etc. C. quinquefasciatus is found up to 1930 metres altitude above sea level.
The rapid and indiscriminate spread of urbanization is creating favourable habitats for the ever- increasing spread of this mosquito in Africa and Asia. Its proboscis is of uniform colour without any pale ring, while the abdomen has brownish yellow basal bands.
C. quinquefasciatus breeds in enormous numbers in the spring, developing in rain barrels, horse troughs, ground pools, ditches, cement pits, open drains, masonary tanks, tin cans, cisterns, cesspits, flooded latrines, catch basins, pits, in which coconut husks are soaked in South India, or in any standing water near houses, sewers with high organic pollution. It may remain alive up to 210 days. Average life span is 2.5-3.0 months. Adults can fly to a distance of 5 kilometres from their breeding places.
Adult females deposit their brownish black eggs in a raftlike mass, appearing like a speck of soot on the surface of water. From 50 to 400 eggs may be found in these masses. The individual egg is ovoid and floats with the narrow and pointed end upwards. A single female may deposit several masses during her lifetime.
The egg stage lasts 24-36 hours; larvae take 7-10 days to mature; pupae take about 2 days to become adults. The life-cycle is completed in 10-14 days. The larvae undergo four moults. The female mosquito is a night-biter and the oviposition takes place at night. Their maximum biting reflex is at 31 per cent relative humidity.
There is no proof of hibernation or aestivation in this species. The highest activity has been noticed in the month of March when the overall average density in 6.5 man-hour. The adults take shelter in cowsheds, dark corners of dwelling houses, behind dumped clothes and cupboards, and also under fallen leaves in gardens.
They take rest by day on clothes and furnishings in houses, as well as on walls and roofs. Deforestation, establishment of plantations, urbanization, thatched roofs and mud huts are associated with increased mosquito population. Construction of dams, ditches, ponds, lakes, reservoirs, roadways and railways are apt to encourage mosquito breeding.
C. Genus-Anopheles:
One of the characteristics of the Anopheles is the occurrence of the sub-species complex. A. maculipennis Meigen complex of Europe has been divided into seven sub-species. There are 5 members of A. gambiae Giles complex of Africa. Anopheles hyrcanus (Pallas) forms a complex in central and southern Asia, north Mediterranean regions and Libya.
Two distinct races are found in A. stephensi Liston in India. The various Indian mosquitoes exhibiting races within the species are A. stephensi Liston, A culicifacies Giles , A. philippinensis Ludlow, A. maculatus Theobold, A. aconitus Donitz, A. fluviatilis James, A. leucosphyrus Donitz and A. sinensis Wiedemann.
Anopheline mosquitoes are found in all parts of India, from the sea level up to an altitude of 3,530 metres whereas A. gigas var. simlensis has been found at Kedarnath in U.P. In general, the number of species along the sea coast or in the plains is smaller than in the hills and near the foothills. There is a gradual falling-off in the number of species from east of India, bordering Southeast Asian countries, to the west in areas bordering Pakistan.
Most species can tide over the unfavourable seasons by either finding ecological niches with microclimates which are suitable for their survival or through larval survival in habitats which are not normal to them. Unlike Aedes eggs, eggs of Anopheles are unknown to survive prolonged desiccation.
The larvae of A. jeyporiensis bury themselves in wet sand and emerge again after rains. Hibernation in the adult stage may occur in temperate zone species. A. culicifacies and A. aconitus are able to survive the dry season in Sri Lanka and Myanmar. Hibernating mosquitoes may live up to six months.
Anopheles adults, on an average, survive for about one month. The life span of female A. culicifacies is 8.34 days. The male may live up to 8 days. Males do not fly a considerable distance. They usually remain near the breeding places. A. sundaicus (Rodenwaldt) can fly 2.5 km. In Panama, the flight range of A.albimanus Wiedemann is 19 km.
A typical anopheline egg is boat-shaped with lateral floats attached to both sides. Certain Anopheles species and their races can be indentified by the characteristic floats and egg- colour. Usually, they lay eggs at night, and oviposition may continue for 2 or 3 successive nights in various species.
Eggs are not so resistant to drying in comparison to Aedes but may survive three weeks on drying muds. Eggs generally hatch within 2-3 days. Very few Anopheles species pass the winter in egg stage with the exception of A.walkeri. Anopheles larvae lie horizontal to the water surface.
Four larval stages are usually completed in a week in the tropics. The larval stage may be delayed in some Anopheles species. By examining the larva, various species of the mosquito can be identified.
The larval habitat may be different for different species. The antennae of Anopheles larvae gradually taper from base to apex with a small number of hairs. The dorsal aspect of abdominal segments possesses palmate hairs on the lateral aspects. Thoracic palmate hairs may be present in some species.
On the eighth abdominal segment, there is a pair of respiratory openings. Diapause in the larval stage occurs in some species. In the Punjab and North West Frontier region, Anopheles mosquitoes probably pass the winter in larval form. The pupal stage usually lasts about 2 days.
3. Sand Flies, Phlebotomus Argentipes Annandale & Brunetti (Diptera: Psychodidae):
Several species of sand-flies are known in the world. They bite man and act as carriers of such diseases as kala-azar, three-day fever, tropical ulcers, etc. In India, P. argentipes is the most widespread and acts as a vector of kala-azar virus. Only the female flies suck blood. Besides man, they bite some other warm-blooded animals.
The flies are dark, very small (2 mm) and look like moths. The legs, body and wings are covered with long coarse hairs. There are no cross veins in the wings. The larvae bear a number of spines in transverse rows on each segment. The terminal segment has two long dorsal bristles.
Life-Cycle:
The fly remains active throughout the year. The females lay eggs in dark damp places where there is an abundance of organic matter. The larvae emerge in about one week and they feed on decaying nitrogenous matter and grow to maturity in four stages in about one month. They transform themselves into pupae and emerge as adults in about 10 days. The flies live for 8- 10 days and the life-cycle is completed in two months. They pass through a number of generations in a year.
Damage:
The flies are active at night when they attack silently and inflict a very painful bite while sucking blood. The ankles, dorsum of the feet, wrists, inner elbows and the knee-joints of human beings are preferred for biting. The act of biting is followed by intense itching and wheel-like swelling.
Control:
(i) Preventive measures to control sand-flies include cleanliness in and around human habitations, so that flies may not find any suitable place to breed.
(ii) The sand-flies can be killed by surface spraying with lindane 5 per cent to serve as residue spray. In addition, the insecticidal application recommended for mosquito control is also effective. Pyrethrum ointment can be used to repel the sand flies.
4. Cockroaches, Periplaneta Americana (Linnaeus) and Shelfordella Tartara Sauss (Dictyoptera: Blattidae):
Although these pests are world-wide, they thrive better in the tropical and sub-tropical climates. The housewife considers them the most obnoxious and filthy insects, especially in the kitchen where these nocturnal omnivorous creatures come out of their hiding-places at night and crawl all over the uncovered foods devouring and ruining them with the foul odour and excreta.
The damage is done both by the nymphs and the adults. In northern India, S. tartara is the commonest species. It is a shining flattened black insect, about 30 mm in length, with its head bowed downwards, so that it is almost covered by the pronotum from above. There are long slender antennae which are used as tactile organs.
The head, the body and the legs are so arranged as to enable it to pass through tiny cracks and holes. P. Americana is confined to South India. The other important species in India are the German cockroach, Blattella germanica (Linnaeus) and B.orientalis Linnaeus.
Life-Cycle:
These pests are most active during the hot and humid season. The females of S. tartara lay cigar-shaped eggs in a bean- shaped dark-brown capsule which resembles a bulging purse. The incubation period is about 2 days in the summer and several weeks in the winter. The emerging nymphs resemble the adults except for their being smaller and lighter in colour.
They are often brooded over and cared for by the mother. The nymphal stage lasts over a month and finally the adults emerge from the moult. They are long-lived. The life-cycle is completed in 4-5 weeks during the summer. There are several generations in a year.
Eggs of P. americana hatch in three weeks during the summer and three months in the winter. The nymphal period is 3-10 months, depending on prevailing temperature. Generally, there is one generation.
Damage:
The sugary and starchy substances in the houses or godowns are ruined by these insects by their excreta and offensive smell does not go even after cooking. They also feed upon old damp books and leather articles. The cockroaches are a common sight in trains, unclean kitchens and restaurants, in old musty buildings and other filthy places.
Control:
(i) The cockroaches can be kept under check by observing thorough cleanliness and preventing infestation by keeping the pipelines leading to the basement and the drains sealed.
(ii) The cockroaches can be killed by spraying the room with malathion/chlorpyriphos 0.5 per cent or by repeated dustings with malathion/carbaryl 5 per cent at night in the corners or on the floor along the walls, taking care that food materials are not contaminated by the insecticides.
(iii) Dichlorvos 0.5 per cent spray may also be used in situations where a rapid knock-down effect is desired. The combined application of dichlorvos and a persistent insecticide can be made for getting both the knock-down and the residual effects.
5. House Crickets, Grylloides Sigillatus Linnaeus and Acheta Domesticus (Linnaeus) (Orthoptera: Gryllidae):
Various species of crickets are distributed throughout the world, A. domesticus being the commonest. This is a pest of household articles and is familiar to all because of its musical but monotonous chirpings. Two species of house-cricket are prevalent in India; A. domesticus, also referred to as the ‘cricket of hearth’ and G. sigillatus; the latter is more abundant.
Both the adults and nymphs damage clothes, starchy materials and pollute food-stuffs. The adults are yellowish brown or straw-coloured, with 2 or 3 segmented tarsi, long antennae and stout hind legs which are used for jumping.
Life-Cycle:
The pest is active throughout the year and is abundant during the monsoon. There is only one generation in a year. The yellowish cylindrical eggs are usually laid in the late summer and autumn, and are found in clusters in the soil or in crevices and dark moist corners inside houses.
They hatch in about one week and give rise to tiny active nymphs which resemble the adults except that they are smaller and wingless. They are omnivorous and feed on all sorts of materials found in the house. They are full-grown in 3-4 months. The crickets are solitary nocturnal insects and hide during the day-time under boxes, behind curtains, pictures, books, etc.
Damage:
At home, these insects are chiefly a nuisance and they disturb by their monotonous chirping produced at night. They will also eat food and clothing. In the field, they occasionally damage crops by chewing roots, underground stems of various plants and the fruits touching the ground.
Control:
The crickets can be killed by dusting the corners and floors of the house with malathion/carbaryl 5 per cent at night, taking care that the food-stuffs are placed at a safe height.
6. Bed Bug, Cimex Lectularius Linnaeus and C. Hemipterus (Fabricius) (Hemiptera: Cimicidae):
This pest is world-wide and is found in the slums, poultry sheds and barns. Once the infestation gets a firm hold, it is very difficult to eradicate it. This is the most repulsive nocturnal bug residing chiefly in dirty old homes. It is a parasite that sucks the blood of human beings as well as that of other mammals and poultry.
The bed-bug is a small bristly mahogany- brown, wingless, rather pear-shaped insect, about 13 mm long, having a distinct odour. Before a blood meal, it is flat and active, but following the meal, it turns oval and becomes sluggish.
Life-Cycle:
Depending upon the favourable warm climate and food supply, the bed-bug may breed throughout the year, although egg-laying is suspended in cold weather. The female lays elongate, whitish eggs in cracks of furniture, behind base boards, under loose edges of wallpaper, etc. She may lay 75-500 eggs at the rate of 3-4 per day.
The eggs hatch in 6-17 days and the tiny nymphs moult 5 times during 6-8 weeks. Normally, an adult female lives 2-10 months. The life-cycle is completed in 15-50 weeks. The adult bed-bugs have been observed to withstand starvation up to a year. Up to 4 generations may be produced in a single year.
Damage:
Damage is done only at night when the bed-bug prowls about, looking for a blood meal. Most of us have felt the bite of the bed-bug as an intensely itching inflammatory wale. The lesions produced in poultry may be so irritating as to cause the birds to abandon their nests.
Control:
The bed-bugs can be controlled by treating the furniture and beds in infested houses repeatedly with malathion 1 per cent.
7. Human Louse, Pediculus Humanus Linnaeus (Phthiraptera: Pediculidae):
This pest is almost world-wide, especially in over-crowded slum tenements, military barracks, prisons, orphanages, etc. The human lice are blood-sucking insects which cause irritating skin lesions and are important in the transmission of certain rickettsial diseases, notably typhus fever.
Three kinds of lice are parasitic on man- Pediculus capitis DeGeer, the head louse living on the skin and hair on the scalp; Pediculus humanus Linnaeus, the body louse living on garments adjacent to the body and Phthirus pubis Linnaeus, the crab louse which infests human hair in the pubic region.
The adult louse is a small, greyish-white, flattened, wingless, six-legged insect, about 1.5-4.0 mm in length and nearly half as broad. It has heavy legs, each of which terminates in a single, sharp, curved claw for grasping. The body louse is typically larger than the head louse and is lighter in colour.
Life-Cycle:
Breeding usually goes on throughout the year in over-crowded, poorly ventilated and comparatively warm dwellings. The female of the head louse lays its eggs (nits) glued to the hairs on the head, whereas the body louse lays her eggs on the seams of clothes. A female lays 8-10 eggs daily until 50-100 are laid by the head louse and 200-300 by the body louse.
The eggs are oval, whitish, about 1 mm in length and have a distinct pebbled lid at one end. The incubation period is about one week. The emerging tiny, slender nymphs begin feeding at once and undergo 3 moultings over a period of 1-4 weeks. The adults live for about one month or more.
Damage:
The damage done by these insects is of three types; the stigma of having this pest which is associated with dirty slum conditions, the irritating itchy skin lesions and the transmission of certain human diseases.
Control:
(i) A powder containing malathion 2 per cent is useful as a delousing treatment. For the control of infested head or body, the application of malathion 5 per cent dust two times at 10-day intervals is very effective,
(ii) Personal cleanliness is essential for obtaining constant relief.
8. Rat Flea, Xenopsylla Cheopis (Rothschild) (Siphonaptera: Pulicidae):
The rat-flea or the Oriental flea is distributed throughout the world. Fleas, in general, are cutaneous feeders, shifting from host to host. The rat-flea is notorious for being the direct transmitter of the bubonic plague (caused by the bacterium Pasteurella pests) among human beings. In the past, the bubonic plague was responsible for almost wiping out certain sections of the human population.
The adult rat-flea is a hard-skinned, very spiny insect, with piercing-sucking mouthparts, concealed antennae, and no wings and with very large legs for jumping.
Life-Cycle:
Breeding takes place throughout the year but somewhat slowed down in cold weather. The eggs are either deposited in dust, dirt or bedding of the human host or laid while the female is on an animal. The eggs lie loosely on the hairs and usually slip into the ground where they incubate for 2-14 days.
They are short, ovoid, relatively large and are laid in small numbers, although the total egg production by a single female may be several hundreds. The young larvae are legless, eyeless and very slender and are whitish. With their chewing mouth parts, they feed on the excreta of adult fleas or on that of mice, rats and other rodents.
The larval stage lasts 1-5 weeks or more. The full-grown larva spins a small, oval, silky cocoon from which it emerges as an adult after 1-5 weeks, although it may pass the entire winter in the pupal stage. It has been observed that it may take 2 weeks to 2 years for a generation of fleas to complete its development under different conditions.
Damage:
The adult fleas, which feed only on blood, cause damage to human beings in 2 ways: first, by their piercing skin bites which cause irritating and itchy skin lesions, especially on the extremities; second, as the principal vectors in the transmission of certain important infectious diseases of man, such as the bubonic plague and murine endemic typhus. The fleas are also intermediate hosts of dog tapeworm and rodent tapeworm.
Control:
(i) The houses should be kept rat-free by keeping cats or by frequent poison- baiting.
(ii) The houses should also be kept clean, well swept and ventilated, with occasional spraying of floors with malathion 0.5 per cent.
9. Black Ants, Monomorium Indicum Forel and M. Destructor (Jerdon) (Hymenoptera: Formicidae):
Being world-wide, black ants are the bore of every house-wife, especially in the tropical and sub-tropical humid climates. There are numerous species of black ants distributed throughout the world. This is one of the commonest troublesome household pests because of its lust for almost every human food and its habit of forming nests in cracks of walls, floors and the roofs of buildings.
The foremost species which invade houses and godowns in India are the small red house ants, Dorylus lahiatus Shuckard, Monomorium indicum Forel, M. destructor (Jerdon) and the large black ant, commonly known as carpenter ant, Componotus compressus (Fabricius).
Life-Cycle:
The ants are fascinating social insects. Each colony consists of 3 castes; the workers, the males and the queen. The workers are modified females. In certain seasons (e.g., the monsoon), the swarming of ants takes place and the winged males and females (young queens) mate in the air, following which the males may or may not die and the queens descend, shedding their wings and start excavating a small nest.
When the cavity is complete, the queen seals the opening and isolates herself for some time until the eggs of her ovaries mature. This may take months and then she lays eggs. Once the eggs hatch, she feeds the white legless grubs on her salivary secretions at the cost of her own body fat and wing muscles. When full-fed, they pupate and the first batch of workers emerges.
They break open the entrance and henceforth supply the food. The subsequent generations of adults are large in body because of better feeding, and as the colony increases in size, additional chambers are added to the nest. It probably takes several years for the colony to establish itself. Ants generally live a long life and their colonies, once established, flourish for many years. It has been reported that one queen lived for 15 years.
Damage:
Damage is done by the workers which get into almost everything that is edible, although they prefer sweets and fats. They also remove grain and seed from stores. They attack wood-works and make holes in the roofs, causing leakage during the monsoon.
Control:
(i) All the holes and cracks through which ants may enter a house or make a nest should be closed. The food should be stored in ant-proof containers. The legs of food cabinets should be dipped in dishes containing water,
(ii) The only sure method is to locate the centre of the colony and destroy the queen and its progeny by pouring large quantities of chlorpyriphos 0.5 per cent emulsion into it.
(iii) In the outdoor situations, it is easy to find out nests of such ants which form ant-hills by throwing out bits of earth while building nests in the ground. Such nests can be destroyed by drenching with about 10-15 litres of 0.5 per cent chlorpyriphos.
10. Wasps, Polistes Hebraeus (Fabricius) and Vespa Orientalis Linnaeus (Hymenoptera: Vespidae):
The adult wasps in India cause damage to various ripe fruits such as pear, peach, plum, grapes and they may also attack the honeybees or cause nuisance in houses and buildings, by inflicting pain upon human beings through stinging. There are two species common in the north-western plains and two are found exclusively in the western Himalayan region. P. hebraeus and V. orientalis are the species found in the plains.
The former is uniformly yellow and the latter is larger and deep brownish with yellow bands across the abdomen which gives a shiny appearance. Both the species make their nests in protected places in houses on the ceiling or in hollows inside walls or trees. Of the mountain wasps, Vespa ducalis Smith is of the same size as V. orientalis but is rust-red and hairy. It makes large nests atop the trees and can be easily seen in forests in the winter when there are no leaves on some of the tail trees such as simbal (Bombyx malabaricum).
The other species, Vespa magnifica Smith, makes its nests in the ground and is the largest wasp in northern India. It is dark brown and hairy, and has a robust look. It is a very devastating predator of honeybees and is seen hovering over the beehives, snapping them with the greatest ease. This species is more common in the higher altitudes, whereas V. ducalis is more abundant at the lower altitudes.
Life-Cycle:
The wasps remain active during the warm summer months and hibernate as fertilized females (queens) during the winter, in cracks and crevices in the ground or in other places of protection. The three species which make exposed nests desert them during the winter and try to come back to the old nests next season.
If, however, the nests have been destroyed in the meantime, they make new ones. The nests of P. hebraeus are simple and rounded and are often seen in ceilings of verandahs and that of V. orientalis are a series of irregular simple nests, generally found in hidden places in walls or in the hollows of trees.
The nests of V. ducalis are conical multistoreyed structures, covered with a protective outer wall with a ventral entrance hole. These nests are common on tall trees. V. magnified makes nests in the ground on a raised place which is not likely to be flooded. There is an entrance hole in the ground that leads to the multi-storeyed nests inside.
In all these species, the first brood in the spring is raised in the old or new nests by the queen alone which lays eggs in the cells. The larvae on hatching remain in the cells and are fed and reared there. This brood consists entirely of workers which, on emergence from the pupae, take over foraging and brood-rearing.
From then onwards, the brood is reared more or less continually. The young larvae are fed on masticated animal tissues obtained by predation on insects or by biting off bits from the dead bodies of animals. Apparently, the sugary foods are also used. The full-grown larvae pupate in the cells which are then capped by the workers. Before emergence, the adults bite their way out of the cells.
There are several broods in a year and the last brood- reared in the beginning of the autumn consists of both male and fertile females which mate, leaving behind the fertilized queens for wintering over. During the cold season, all the workers and the males die, and only the queens survive till the next spring.
Damage:
The damage caused by these wasps is of various types. All of them feed on ripe pears and other sweet fruits, sometimes causing heavy damage. The mountainous species are very serious predators of honeybees and become a limiting factor in the success of beekeeping in certain areas.
Control:
(i) The honeybees can be protected against the attack of wasps by killing them with clubs.
(ii) Their nests should be located and destroyed.
(iii) They can also be killed in the houses or orchards by hanging sugar baits containing trichlorphon as the poison.
11. Book Louse, Liposcelis Transvaalensis Enderlein (Psocoptera: Liposcelidae):
The book-louse, which is world-wide, is a minor household pest. It is found in collections of old books and papers where they remain hidden and feed upon paste and paper. Most of us have seen these creatures on opening an old book where like a tiny speck; a pale insect rushes across the width of a page and disappears quickly. These are tiny, soft-bodied, wingless, light-coloured insects, with chewing mouth-parts and relatively long legs and antennae.
Life-Cycle:
The biology of the order, to which this insect belongs, needs to be thoroughly studied. They usually overwinter in the egg stage, but under warm, damp and dark conditions, they may breed throughout the year. The emerging nymphs are the adults in miniature.
Damage:
The destruction caused by this insect is not usually very significant, but if they are present in enormous numbers, they may damage old rare books. Occasionally, they do harm by feeding upon the flour and cereal products in the kitchen and store-houses.
Control:
(i) The best way to eliminate the pest is to dry out the houses and provide ventilation.
(ii) The old books and paper files should be brushed regularly.
(iii) The articles likely to be infested should be kept in tight containers.
(iv) The paste meant for binding books should contain 5 per cent copper sulphate.
(v) The almirahs and shelves containing books and paper records should be treated with 5 per cent carbaryl dust.
(vi) Heavily infested libraries should be made airtight and fumigated with carbon disulphide or phosphine gas.
12. Silverfish, Lepisma Saccharina Linnaeus and Thermobia Domestica Packard (Thysanura: Lepismatidae):
These insects occur all over the world and are minor household pests. They are usually found in hot and moist parts of a house, such as the basement, among old books and magazines.
There are two species and the more familiar is the silverfish or ‘fish-moth’, L. saccharina, which is a carrot-shaped, soft- bodied, glistening, wingless insect, about 13 mm in length and covered with silvery scales. The other species is the fire-brat, T. domestica, which resembles the silverfish, except for mottled black and white patches on the upper surface of the body and its love for warm places such as fire-places, chimneys and places near the ovens.
Life-Cycle:
These pests are active throughout the year in the warmer climates. All stages may be found throughout the year and the number of generations may vary according to the temperature and humidity of a locality. The female lays a few whitish oval eggs in warm and damp places.
The incubation period is 6-10 days in India. The young ones resemble the adults except that they are smaller. The development is slow and an indefinite number of moultings take place. The insects reach maturity in 7-9 months and the generations overlap.
Damage:
The damage done by this pest is not much. It is, however, a nuisance. It prefers glue and starchy materials, and the insect with its chewing mouthparts may eat book bindings, paper, wallpaper, fabrics, starched clothes, etc. Occasionally, they cause considerable destruction in libraries and to certain fabrics.
Control:
(i) The population of the pest maybe checked by regular cleansing and ventilation of the places. The cracks, if any, should be sealed.
(ii) Poisoned glue pasted on small cardboard pieces to be placed among the books, serves effective bait against these insects. The bait may be prepared by mixing wheat-flour (200 parts), sodium fluoride or white arsenic (16 parts), powdered sugar (10 parts) and powdered common salt 5 parts.
(iii) Dusting the haunts of the pest with malathion 5 per cent is also useful. Alternatively, naphthalene balls may also be kept in boxes.
13. Greater Wax Moth, Galleria Mellonella (Linnaeus) (Leidoptera: Pyralidae):
The honey-bee comb or beeswax in beehives or in stores is attacked by two species of wax- moths, the greater wax-moth, G. mellonella and the lesser wax-moth, Achroia grisella (Fabricius). Of the two, the former is more important in the world. In the plains and lower hills of India, it presents a serious threat to the beekeeping industry, but is rare at high altitudes.
Damage is caused only by the caterpillars which feed on old combs, propolis, pollen, larval skins and other proteinaceous matter, but they cannot live on beeswax alone. A full-grown caterpillar is dirty grey with a brownish head. It is about 33 mm long and is seen moving actively in silken tunnels made in the comb and on the bottom board in beehives. The moth is generally brownish grey and measures 25-40 mm across the spread wings.
Life-Cycle:
The greater wax-moth is active from March to October and passes the winter mostly as a hibernating larva and sometimes as a pupa. The moths emerge during March-April and mate outside the beehive. The females re-enter the hives usually at night when the bees are not active. They lay spherical, smooth and creamy white eggs in clusters which are hidden in cracks and crevices of the hive or are found right in the combs.
A single female may lay about a thousand eggs during its life span of two weeks. The eggs hatch in 7-18 days and the young caterpillars feed on gnawed pieces of the comb or other debris. As a protection against the attack of bees, they make silken tunnels in the combs or on the bottom board, wherein they feed unhindered.
They pass through 5-7 stages and are full-fed in about 4 weeks in the summer. The full-grown larvae spin thick silken cocoons in which they pupate. The pupal stage lasts about a week and the life-cycle is completed in 6-7 weeks during the active period and it passes through several overlapping generations in a year.
Damage:
The caterpillars eat combs and interfere with brood-rearing by making silken galleries through the cells. In case of severe infestation, the whole comb becomes a mass of webbings in which excreta of the caterpillars is enmeshed. The infested bee colonies often abscond. In the offseason, when the combs are stored, the caterpillars damage them also.
Control:
Caterpillars of the wax-moths can be killed with fumigants, but this method cannot be adopted in the inhabited beehives.
In that case, only preventive and mechanical measures of control can be followed:
(i) All the cracks and crevices in the beehive should be closed with the moulding-clay.
(ii) The hive entrances should be reduced to widths which can be easily guarded by bees.
(iii) All debris on the bottom boards should be removed and cleaned regularly and the caterpillars removed and killed.
(iv) The beeswax and combs in stock should be kept in airtight boxes,
(v) If infestation develops in a store, it should be fumigated with aluminium phosphide, EDCT mixture or methyl bromide.