A Pest is an insect or a small animal which can damage crops, spread diseases to man and other animals.

Types of Plant Pest

  1. Insect Pest: These are insects that are harmful to plant and cause damages to crop on field and at storage
  2. Crop eating insects can damage crops in various ways, their larvae chew their way into the roots while above surface insects feed on leaves, flowers and seeds./
  3. Sap-sucking insect: This group of insects constitute major problem, they weaken plant by stealing the energy rich sugar in sap and they also spread viruses that can cause disease. Example is aphid .
  4. Biting and chewing insects: They have the ability to destroy crops by eating up the leaves of young crops like maize, guinea corn, yam and vegetables.
  5. Piercing and sucking insects: These are insect pests having mouth parts adapted for piercing and sucking of crops. They pierce into young developing fruits, seeds and young stems and suck up the sap. Some of them inject poisonous chemicals into their saliva and cause distortion in growth of attached crop. Examples are cotton stainer, mealy bud, weevils and aphids


Some worms are subterranean, they feed on juicy roots of plants and destroy them making such plants to fall e.g. corn, while other worms chew their way up and feed on leaves, stems, flowers and feed  of plant.

(a)        Pod borer: They bore into fresh pod, eat up the seeds, introduce diseases and leave the pod to decay e.g. beans and soya beans

(b)        Stem borer: They bore holes into stem of crops, eat up the tissue and weakens the plant support e.g. maize, sorghum and millet

(c)        Army worm: The larvae of the worm engulf leaves and stem which retard growth and plant nutrient and reduce farm yield of crops e.g. maize, millet and sorghum

  1. ANIMAL PEST: These are animals either mammals or birds which destroy crops on the field

(a)        Mammal pest: They can invade maize farm and consume it to reduce the level of harvest. They can also destroy ripped palm fruit, yam and cassava crops example are monkeys, grass-cutter, ground squirrel, bush rat or rodent

(b)        Bird pest: They destroy grain farm within few days. They feed on young and dry corn, punch cassava and yam tubes and destroy groundnut. They can also feed on grains and banana e.g. bushes fowl, guinea fowl, village weaver birds.


  1. insect pests such as grasshoppers can destroy the vegetation of several kilometres within few days

ii          Pests compete in feeding with humans and their effect can lead to scarcity or famine

iii.        Crop pests reduce the quality and quantity of infested crops, seeds and fruit

  1. They can cause financial disaster for farmers when they attacked and destroy stored produce
  2. They make the farmer to spend much money on pesticides and other method of control
  3. Some of the pests are agent of disease carrier deadly to both man and plant

             Control Of Pests

  1. Chemical control is by the use of chemical substance that will bring about the killing of the pest e.g. Aldrin and vertox 85, Gammalin 20 and Didimac 25
  2. Cultural method of control involves the use of season, crop rotation, regular weeding, correct spacing and early harvest to confront the menace cause by pest

iii.        Physical method of control includes the use of scaring, killing and collecting pest for mass destruction. It also involves setting of traps, shooting, catapulting, scare-crows and the use of farm drum.

  1. Biological control: it involves introduction of natural enemies of the pest to consume the pest or to keep their population under control

  Life cycle of yam Beetle

life cycle yam beetle

The pest destroys large quantities of yam tubers annually by making hole or boring into the tubers. They bore into the tubers. The beetles live in the soil and in breeding seasons, they lay their eggs in damp places between November and December. The eggs hatch into larvae feeding on decaying matter at first, then on the root of grasses. They change into pupa and by March the adult beetle emerges and set off for feeding migration normally between April and June. They burrow themselves into the soil and it is here that they attack the yam tubers. They continue feeding up to October before setting off on breeding migration in November-December to seek damp places to lay their eggs and the cycle begins again.

Life Cycle of Rhinoceros beetle

life cycle 4hincerous

Rhinoceros beetles are pests that are found on the leaf bases of oil palm trees. They have potential or killing the tree. The life cycle begins when after mating the female beetles lay eggs at the bases of leaf stalks on live palm or on trunks of dead trees. Two weeks later, the eggs hatch into larvae having powerful mandibles which they use to eat dead wood.

After ninety days therefore, the larvae changes into a pupa in a cacoon, then 2-3 weeks later the adult emerge. The adult also feeds with the mandibles by burrowing into the dead wood like the larva. The effective means of control is by burning dead and discarded trees from the oil palm plantation

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