Here is an essay on ‘Non-Insect Pests and Its Control’ for class 11 and 12. Find paragraphs, long and short essays on ‘Non-Insect Pests and Its Control’ especially written for school and college students.
A number of non-insect pests like mites, nematodes, rodents, birds, snails and slugs are known to damage agricultural crops. Among the mammal pests, rats and mice are at present the most abundant and destructive in the field as well as inside the houses and godowns.
They damage practically all the field crops but some food crops like wheat, rice and groundnut seem to be their favourites. A number of large mammals which used to destroy crops have now dwindled in number and, in fact, efforts are being made to preserve some of this wild life in sanctuaries and national parks established in various states of India.
It is interesting to note that only 25 of about 1200 species of birds found in India (i.e., only 2.1%) have been reported to inflict damage to crops and fruits. It would appear that, in general, the granivorous birds became abundant with the increase in area under grain crops and the subsequent storage of grain in godowns or bulk storage. Several species of snails and slugs also inflict considerable damage to cultivated crops.
1. Essay on Fruit Bats:
Indian Fruit Bat, Pteropus Giganteus Brunnich (Chiroptera: Pteropodidae):
Bats are the only flying mammals and the Indian fruit-bats are often seen in the Punjab plains hanging on electric wires, after having been electrocuted accidentally. Their roosting abodes lie at various places in the Kangra Valley (Himachal Pradesh) and with the ripening of fruits, they migrate temporarily to higher or lower altitudes.
They are confined to the tropical and sub-tropical regions of India and do not live permanently in the temperate zones. These bats are to be distinguished from the dark-brown or smoky smaller insect-eating bats, which are not harmful except for being a nuisance in and around houses. In South India, P. edwardsii is the common species; P.vampyrus and P. edulis are present in Malaysia.
The fruit-bats or flying foxes have a long range flight and are known to visit fruit orchards in Amritsar at night and return to their roosting places in the lower Himalayas before daybreak. These bats have long-snouted fox-like faces and light-brown fur with darker patches.
In between the fingers of their fore-arms, there are loose folds of skin extending backwards along the legs. These are the ‘wings’ used for flight and the claw-like toes are used for hanging upside down. Their body length is 18-25 cm and they measure 1.2 metres across the wing spread.
Habits:
Bats are unique mammals as they suckle their young ones like other mammals but fly like birds. There are few barriers that hinder their flight and yet their distribution is limited by climate. Bats prefer to live in tropical, semi-evergreen, moist and dry deciduous zones. They do not penetrate into evergreen rain forests. In the desert or semi-desert areas, they are found only at those places where man has planted fruit-trees.
The distribution and movements of these bats are influenced by the flowering and fruiting of trees that provide them with food. According to the availability of ripe fruits, the bats may be abundant at a given place in one season and absent in another. Their breeding also coincides with the fruiting season.
During day-time, the Indian fruit-bats rest in large numbers on tall trees, such as banyan, fig, tamarind, etc. They persistently stick to the same location, except when they migrate temporarily, following the warmer weather and the ripening fruits.
Their winged arms and feet can be used for holding food and for walking, but during the active season, they eat, nibble and drop the damaged fruits or take them away to their roosting places and thus they cause large number of seeds to accumulate under the trees. During cold weather, they remain inactive and suspend their destructive feeding activities.
Fruit-bats are essentially nectar-or fruit-juice feeders. They munch the fruit pith and throw away most of the morsel while in the upside down hanging position. They are voracious feeders and, in this manner, use or destroy more than their own weight of fruits every day. All this is done at night in the dark and it is possible for them to do by their remarkable power of echo- sounding (precursor of radar invention), unmatched hearing power and the most sensitive sense of touch in their wing membranes.
Damage:
Fruit bats are active at night, flying long distances to reach the orchards. They munch, drop and destroy huge quantities of fruit such as pear, plum, peach, guava, mango and apple. In South India, they damage coconuts. The orchards invaded by flying foxes are littered with remnants of fruits picked and destroyed.
Control:
(i) Many methods, such as keeping the orchards well-lit at night, creating noises, shooting, etc. have been tried by individual orchardists with varying degrees of success.
(ii) The most accepted and perhaps the most effective method is shooting them at the roosting places.
(iii) Killing them by the detonation of explosives on the roosting trees has also been tried with good results under the supervision of the staff of the Inspector-General of Explosives, Government of India.
2. Essay on Mammals:
1. Monkey, Macaca Mulatta Zimmerman (Primates: Cercopithecidae):
The common monkey is found in the Himalayas, Assam, Myanmar, northern and central India (as far south as the Tapti and the Godavari). It is an animal with the crown hair radiating backwards and with orange-red fur on its loins and rump. Monkeys live in large troops and destroy fruits, maize cobs and steal away eatables from shops, temples and houses. They prove themselves to be a great nuisance. They pluck and throw away much more than what they actually eat.
Habits:
They live in large groups near villages, towns, in groves or on the outskirts of forests and show a preference of the open country. They invade gardens and fields of crops in the morning and evening. In the afternoon, they rest in the shade of trees on the roadside near temples, ponds and shady places. They are often seen bathing in water, with the babies clinging to their mothers. The monkeys can swim and they keep themselves cool by frequent dips. During winter, they acquire a thicker coat as protection against cold.
The social troop life of monkeys has not been studied thoroughly, but among them there seems to be a male leader who apparently dominates others. The majority in a given group are females and young ones. In the western Himalayas, mating commonly takes place in August- September and the young ones are born from March to May.
However, sex life is persistent and mating may take place at any time of the year and this instinct seems to be the main driving force for social and community living. Fur-picking is another social habit that binds the members together. This habit is not meant to search and remove lice and fleas as is commonly thought because monkeys are generally free from these external parasites.
Damage:
When the maize crop and fruits ripen in the lower Himalayas, large troops of monkey descend from the forest edges to invade towns and villages. The devastation caused by them is often complete and extremely wasteful.
Control:
(i) Owing to the religious sentiments of the people, shooting, killing and poison baiting are not recommended,
(ii) Under contract with the Government, authorized persons may be allowed to catch monkeys with various types of nets and snares, and the captives can then be kept in laboratories for experiments in medicine or exported for the same purpose.
2. Indian Porcupine, Hystrix Indica Kerr (Rodentia: Hystricidae):
The Indian porcupine is found throughout the Indian Sub-continent and parts of western Asia. In the western Himalayas, it is found up to 2,400 metres above sea-level. This rodent is very characteristic in having quills or spines (modified hairs) on its body. The quills may be solid or hollow, depending upon their location and they possess deep-brown or black end rings.
In southern India, the animal may acquire a bright rusty red or orange hue and is often given the misnormer ‘red porcupine’. In the central and eastern Himalayas up to an elevation of 1,500 metres, another species, H.hodgsoni (Gray) is prevalent.
Habits:
The Indian porcupine is found in all types of habitat, dry or humid, open land or forest, rocky hillsides and the undulating plains. Although burrows are not essential, the porcupine generally lives in burrows they dig. There is considerable earth lying around the mouth of a burrow and some pieces of chewed-up bones or horns may also be seen. The bones and horns supply the much needed calcium for the proper growth of the quills.
When irritated or alarmed, the porcupine erects its spines, rattles the hollow quills and charges backwards with great speed. The quills are driven deep into the enemy and can be fatal even to some of the large animals, like the tiger. New quills grow under the old ones which are shed. Porcupines breed in the spring and both parents live with 2-4 young ones, which are born with their eyes open.
Damage:
This rodent causes damage to vegetables, grains, fruits and crop roots. During daytime, it hides in the vegetation near the fields, in grass, bushes and scrub. At night it comes out and causes damage. Sometimes, it even tunnels through the walls of gardens to reach food.
Control:
(i) The porcupine may best be killed with a shot-gun.
(ii) Trapping is obsolete and not humane. The animal has a strong sense of smell; therefore, poison-baiting is not so effective.
(iii) It can also be killed by fumigating the burrow with phosphine and closing the entrance.
3. Jackal, Canis Aureus Linnaeus; Dhole, Cuon Alpinus (Pallas); Wolf, Canis Lupus Linnaeus (Carnivora: Canidae):
(a) The jackal or giddar has a wide distribution ranging from south Eastern Europe to India, Myanmar and Thailand. It belongs to the dog family and there can be successful crossing between a jackal and a wolf or a dog, although under natural conditions, free interbreeding is not noticed because of their characteristic habits.
Jackals are notorious for their damaging activities in fields of ripe sugarcane, maize, musk- melon, water-melon, etc. A full-grown jackal is about 38-43 cm in height, 60-75 cm in body length excluding the tail and weighs about 8-11 kg. It is the size of a small dog and has a coat which is a mixture of black, white and mud-buff. It is shy during the day-time.
Habits:
Just before dusk, the jackals are heard howling with a long-drawn eerie voice. Although jackals are found in mountainous areas, they are common in the plains, near towns and villages and near the places of cultivation. During the day, they hide in holes in the ground, unused buildings or in dense grass. They generally go about alone but sometimes form packs of two or three, living as scavangers on carcasses.
They are essentially omnivorous creatures and also feed on maize cobs, musk-melon, watermelon, sugarcane, and fallen ber fruits, etc. They breed all the year round and lay their young in hollows in the ground or other sheltered places. The average life of a jackal is about 12 years.
(b) The Indian wild dog or dhole is widely distributed in central eastern Asia, Manchuria, Malaysia and India. Unlike the jackal, the dhole is essentially a carnivorous animal. It is bigger than the jackal and is much like a domestic dog in general appearance, the body being rather long like that of a wolf.
It is relatively short in the leg and the muzzle, with ears rounded at the tips and the trail quite bushy. It differs from wolf in having six molar teeth in the lower jaw, whereas the wolf has seven. The dhole has also 12-14 teats as compared to 10 of the dog. It has a distinctive red coat which may vary in tone with the season.
The wild dogs live in forests and sometimes in the open countryside. In India, however, they keep entirely to the forest, there being plenty of food, shade and water. The wild dogs have a social life because of their prolonged association between the parents and young ones. One or more families may comprise the pack.
They are very effective in killing quite large animals such as the deer, the buffalo, the bear or even the tiger. Their main breeding season in southern India is November- December and 4-6 young ones are born in January-February. The young ones are sheltered by the mother in a cave or in some other place of protection. Several families may breed together in a colony.
Although this jungle creature mostly preys upon deer, antelopes, etc., sometimes it may also attack domesticated animals like cattle, buffaloes, sheep and goats.
(c) The wolf or bheria is widely distributed in Europe, North America and in a greater part of Asia. In India, they are common in open regions. In the western Himalayas and Kashmir, they have a nomadic life and come down to the valleys in winter. The hollows in mountainsides or small caves and cavities in rocks provide them shelter in the cold weather.
In the desert areas of India, the wolf may dig burrows in sand-dunes for protection against the sun heat. They breed at the end of the rainy season and the young ones are born in December. In the Himalayan region, however, they are born in spring or in early summer. There are 3-9 young ones in a litter and the span of life is 12-15 years.
The wolf hunts deer, rodents, wild sheep, gazelle, black-buck and other animals during the day as well as during the night. It occasionally attacks domestic animals such as sheep, goats and cattle. Where human habitations are close to the forest, the wolf may even attack man and carry off small children.
Control:
(i) All the three pests can be killed by shooting.
(ii) For the protection of musk- melon and sugarcane against jackals, meat poisoned with strychnine (300:1) is quite effective.
(iii) For the protection of a flock of sheep against wolves, shepherds in the Himalayan region keep one or more dogs of the Gaddi breed. The dogs are very strong, alert and faithful. They give a good fight to the wolves and provide effective protection to the flock of sheep.
4. Long-Eared Hedgehog, Hemiechinus Auritus (Gmelin) (Insectivora: Erinaceidae):
The long-eared hedgehog is deep brown or almost black and is found along with another species, the pale, light-coloured hedgehog, Paraechinus micropus (Blyth). The hedgehogs are confined to the dry western and north western areas of the Indian Sub-continent. One race of the latter species is also found in the plains of southern India.
The long-eared hedgehog has a snout which resembles with that of a pig; hence the name hedgehog. It has a stout body, a short tail and stubby legs furnished with claws. The eyes and the ears are well-developed and there is a dense mat of spines on the back and sides of the body. At the back and flanks, the skin is loose. At the time of danger, the animal feigns death and the skin covers the rolled-up body. The pointed bristles give protection to the animal.
Habits:
The hedgehog is a nocturnal animal and during the day-time, it lives in sand holes or underneath thorny bushes or grass. The young ones are produced inside holes lined with leaves or bits of grass. They are blind at birth and their spines are soft and flexible. The hedgehogs are active throughout the summer and their activity is reduced greatly in winter.
The animal comes out at dusk for feeding and retires at dawn. Its main food consists of insects, worms, lizards, rats, but it also feeds on fruits and roots of tuber crops. At places, the damage to nurseries, vegetables or tuber crops might be quite serious.
Control:
The animals can be killed by fumigating them in their holes with phosphine. After placing one tablet (3 g) of aluminium phosphide in the burrow, the entrance hole should be plugged with soil.
5. Wild Boar, Sus Scrofa Linnaeus (Artiodactyla: Suidae):
The wild boar is widely distributed in the Indian Sub-continent, Myanmar, Thailand, Malaysia and Sri Lanka. The male has well developed tusks, measures 0.9 metres at the shoulder and may weigh 250 kg. The animal is black rusty brown and has a sparse coat of white hair and a mane of black bristles. The new-born pigs are brown with black stripes.
Habits:
The wild boar lives in scant jungles or grass and has high intelligence and great courage. Its sense of smell is acute and eyesight and hearing are moderate. It breeds in all seasons and is very prolific. While pairing, the animals collect in groups of 150 or more, the master boar being in the centre. The gestation period is four months and there are 4-6 young ones in a litter, which are protected by the mother. After breeding the males may live alone or in the company of one or two males or females.
After the rains, the boars are commonly seen in tall crops of sugarcane, maize, etc. They feed early in the morning or late in the evening and are extremely destructive. They are essentially omnivorous and may feed on crops, tubers, roots, insects and carrion. Their population has declined very much in areas where jungles are receding, but at places they are still a great nuisance.
Control:
(i) The best and most effective method is to shoot them at sight.
(ii) The old method of ensnaring by leading them into pitfalls with sharp bamboo sticks at the bottom is not a humane method of killing.
6. Sloth Bear, Melursus Ursinus (Shaw) (Carnivora: Ursidae):
The sloth bear is found in the forest areas of the Indian Sub-continent from the base of the Himalayas to Sri Lanka. This species is distinct from the larger Himalayan black bear (Solenarctos thibetanus) which normally lives near the tree-line. During winter, it comes down to 1,500 metres or so.
The sloth bear is 0.6-0.75 metre tall at the shoulder and 1.35-1.67 metre in length. The male is bigger than the female and weighs 125-145 kg. It is dull black with a brownish tinge. It has an elongated muzzle with long, dull, unkempt hair, short hind legs and is the most unattractive of all bears. There is a white V-shaped breast mark and the muzzle and tips of the feet are dirty white or yellow.
Habit:
By habit, the sloth bear prowls at night when it looks for food. During day-time, it retires to the shade of boulders or projecting rocks. When the weather is cloudy or cool, it may remain active even during the day. The bear lives in forests and comes near human habitation, particularly in the autumn season when there may be a dearth of food.
Mating takes place in the summer and after a gestation period of 7 months, the female gives birth to cubs in December or January. When they grow sufficiently strong and have a good hold, they are carried by the mother on her back. The mother cares for the young ones for 2-3 years till they attain maturity. In captivity, the sloth bear is known to live up to 40 years.
The sloth bear is omnivorous. It feeds on fruits, berries, roots, insects, termites, sugarcane, maize and in time of dearth, even on carrion. The combs of the domesticated and wild honeybees make their most prized food and they take great pains in climbing up the trees for getting hold of the combs or they may shake the bush or branch of the tree till the combs fall to the ground. The Indian honeybee, which lives in tree hollows, is also attacked by this animal.
The domesticated bees kept in modern hives have to be protected as the bear has the habit of turning over the hive in order to reach the comb and honey. Towards autumn, when natural food in the forest is scanty, the bear comes out to the cultivated areas and does considerable damage to sugarcane and the maize crops, destroying more than it actually eats. In that season, it is also likely to encounter human beings whom it may attack.
Control:
(i) Killing with shot-guns is the only sure method of getting rid of this animal.
(ii) It is afraid of the human voice and fire or a strong source of light. When moving about late in the evening, people living near jungles walk in groups talking loudly and invariably carry a burning torch or lantern.
7. Blue Bull, Boselaphus tragocamelus (Pallas) (Artiodactyla: Bovidae):
The blue-bull or nilgai is found in the Indian Sub-continent, from the base of the Himalayas to Karnataka. It is not found in Assam or Bangladesh. The males of this antelope are 1.2-1.4 metres high, have short horns and are horse-like in build with a low hump. There is a tuft of black hair hanging from the throat.
Their colour is iron grey with a white ring below each fetlock and two white spots on each cheek. The females are smaller and lighter in colour and are not so ungainly in appearance. The blue-bulls avoid dense forests and roam about in the hills or in the plains covered with grass or patches of scrub where there might be a few trees.
Like other antelopes, the blue-bull keeps visiting the same spot to rest. Generally, there is a large accumulation of droppings at such places. They do not drink water for quite some time, even in hot weather, and generally they live in herds of 4-10, comprising bulls, cows and calves. They breed practically in all seasons and the gestation period is 8-9 months.
In many parts of India, people refrain from killing the blue-bulls because of the misconception that it is a close relative of the cow which is considered sacred. The animal breeds unhindered and may become quite a destructive pest of crops. It feeds on freshly fallen flowers of mohawa (Madhuca latifolia), leaves and fruits of her (Zizyphus spp.), grass, and may also freely enter the cultivated fields. It feeds late in the morning or early in the evening and may cause much damage to the wheat crop.
Control:
It is rare now that this animal is a pest because man has killed it indiscriminately for sport and food. Thus, like many other species of birds and mammals, its population is dwindling so fast that it may become extinct. The spotted deer or the chital has met a similar fate in the Terai region of Uttar Pradesh.
3. Essay on Snails and Slugs:
Snails and slugs are soft-bodied animals belonging to the order Stylommatophora and class Gastropoda of the phylum Mollusca. They are the animals without backbone, having asymmetrical, unsegmented and spirally coiled body. While snails have a well-developed shell, slugs have only a rudimentary shell often enclosed in a visceral hump. Snails and slugs are hermaphrodites but there is reciprocal exchange of spermatozoa as they mature before development of eggs.
Self- fertilization is prevented. They lack good protection against dehydration; hence they avoid direct sunlight and environments with a low relative humidity. They hide during day time in moist places or under debris and feed mainly at night when the temperature drops and the humidity rises. Snails secrete light yellow slime and slugs secrete colourless slime which becomes silvery after drying.
Snails have been reported to cause serious menace to the cultivated crops in many parts of the world. In India, 1500 species of land snails occur but the number of species of slugs are limited. Among these nine species of snails and 12 species of slugs have been reported as pests of ornamental plants, vegetables, fruits and field crops.
The common snail, Helix spp., is found in Himachal Pradesh, Uttar Pradesh, Andhra Pradesh, Bihar, Maharashtra and Orissa. Another phytophagous species, the giant African snail, Achatina fulica Ferussac, has been reported as a serious pest of fruits, vegetables and ornamental plants in coastal areas of Orissa, West Bengal, Assam, Tamil Nadu and Kerala.
The common garden slug, Laevicaulis alte Ferussac, has been observed feeding on a number of ornamental plants including balsam, portulaca, pot-marigold, verbena, dahlia, cosmos, narcissus and lily in Punjab and Himachal Pradesh. The black slug, Filicaulis alte Ferussac feeds on the seedlings of several economically important plants. Another slug, Umax spp., occurs all over India.
Life-Cycle:
The giant African snail, A. fulica lays 50-200 eggs once a year on the soil surface or a little below. It lays about 1000 eggs in its life span of 5 years, out of which about 80 per cent are viable and hatch within a week. The shell and body of the snail keep on growing till about 8- 12 months. The life span of this snail is 3-5 years.
The garden slug, L. alte lays eggs in groups of 6 to 45 in moist soil. Maximum egg laying is observed in the month of September. Eggs are oval, whitish or creamish in colour and transparent, strung along a thread. Incubation period ranges from 9 to 18 days with an average of about 13 days.
Adults mature within a period of 240 to 323 days with an average of 271 days and measure 55 mm in breadth and 50 mm in length. They are found in soil under debris and survive during unfavourable conditions like food scarcity and low moisture during summer months. They remain active throughout the year but their severity is noticed in cool and damp situation.
The brown slug, F. alte lays dirty creamish white spongy eggs in masses (74-80 eggs/mass) on damp soil in polythene bags containing nursery plants. Newly hatched juveniles resembling adults in colour and appearance tend to remain close to the hatching spot and start feeding immediately. They become mature and start egg laying at the age of about 8-9 months and lay eggs twice a year. The adult is about 8-0-8-5 cm in length, 1-5-2-0 cm in breadth and 7-8 g in weight. Average life span is 390 days with the longest being 567 days.
Damage:
Snails and slugs appear as sporadic pests in those places where damp conditions prevail. They may also appear in large number on roads and runways, creating problems during the taking off or the landing of the aircraft. Snails and slugs are polyphagous, feeding on a wide range of host plants. The giant African snail is known to feed on 227 host plants. The slugs have been reported to feed on celery, lettuce, cabbage, tomato and a number of ornamental plants.
Snails and slugs completely devour the small leaves while mature leaves show holes on them or are eaten away around the edge. Thicker leaves are mostly rasped on the lower surface. Mine-like holes and tunnels are bored on tuber, roots and bulbs. Sown seeds of wheat in soil are completely hollowed out starting from the embryo.
In case of slug damage to tomato fruit, complete pericarp is eaten away within an overnight period leaving behind the inner core. The damage from feeding by slugs can be quite extensive, resulting in large irregular holes in plant leaves, debarking the stem near ground, cutting stem of seedlings and roots of plants.
Snails and slugs act as carriers of propagules of plant pathogens. Spores of Alternaria sp., Fusarium sp. and Phytophthora sp. have been found in the faeces and the slime. The snail, A. fulica is known to transmit black rot disease caused by Phytophthora palmivora Butl. on cocoa. The infestation of snails and slugs in the field can be detected by the slimy trails left behind by them as they crawl about.
A. fulica has been reported to cause economic damage to crops of Cucurbitaceae (46%), Basellaceae (39%) and Dioscoriaceae (35%). F.alte is known to cause significant damage to seedlings of marigold (97 %), cabbage (75 %), balsem (69 %), coriander (69 %), portulaca (59 %), zinnia (58 %), sponge gourd (53 %), brinjal (51 %), spinach (48 %) and cauliflower (20 %).
Control:
(i) Collect snails especially during midnight and both snails and slugs before dawn and after dusk. These should be destroyed in 10 per cent solution of common salt or in boiling water and buried in the fields away from the populated area.
(ii) Keep area under crops free from weeds, creating a belt of clear land around garden or farm and use barrier strip of dehydrating chemical like common salt, quick lime or copper sulphate.
(iii) Smooth copper or zinc sheets (0-8 mm thick) can be used as mechanical barriers. The copper sheets must reach a height of 5cm above the soil surface, the zinc 20-25 cm. The upper edge of the barrier is bent through a right angle twice. It should be buried to a depth of about 30cm below the soil surface.
(iv) Poison bait consisting of 10 per cent carbaryl 50WDP in wheat bran having 6 per cent mango flavour can be used to attract and kill the pests. Offer 2-0 g of this bait on paper pieces to pests at 2 m distance in the evening. Collect dead animals for the next 2-3 mornings and bury them in soil.
(v) Spray copper sulpate (3%) @ 12kg dissolved in 400 litres of water per ha.
(vi) Dust 15 per cent metaldehyde @ 50 kg per ha or spray 50 per cent metaldehyde powder @ 10 kg per ha in 500 litres of water per ha or sprinkle 5 per cent metaldehyde pellets around infested fields.