The general principles of pest control are based on the reduction of the pest population to a level so that the cost of control is insignificant.

The methods of preventing and controlling crop pest include:

  1. Physical/Mechanical control
  2. Cultural/agronomic control
  3. Chemical control
  4. Biological/ natural control
  5. Quarantine regulation
  6. Legislative control
  7. Sterilization by radiation

Physical/Mechanical control method

  1. Hand picking and destruction of pest such as beetle, grass hopper, stem borer e.t.c.
  2. Trapping- This can be used for rodents and other livestock
  3. Air tight storage of grains prevent pest infestation
  4. Scare crow- it is used for scaring birds and monkeys off the farm.

Cultural/Agronomic control method

  1. Timely harvesting- Crops should be harvested as soon as they mature to prevent crop pest infestation.
  2. Crop rotation- when crops are rotated, the crop pest that feed on the previous crops are not changed but remain on the soil. When the pest cannot get a suitable host plant, some of them will die as a result of starvation.
  3. Timely weeding- pest usually hide in the weed within the farm. Therefore, weed should be removed as soon as they appear on the farm.
  4. Early planting- when crops are planted early, they develop and mature before the insect pest infestation.
  5. Use of resistance varieties- some varieties of some crops can survive the attack of pest more than other species of the same crop.
  6. Soil tillage- deep tillage exposes the eggs, larvae and adults of insect pest and also the rodents from their hideouts to be killed.
  7. Proper drying of products- drying of grains or produce from the farm to the moisture content level below 12% limits will reduce insect pest development, reproduction and survival.
  8. Bush burning- this involves the burning of bush within the area to eliminate pest. During the process, the useful soil organism such as millipedes, earthworm, and centipedes are destroyed yet burning is very effective in destroying insect pest and their eggs.

Biological/Natural control

This involves the use of natural enemies of pest to control pest. For example: parasite and predators- some insect feeds on another insect for their survival. For instance lady birds eat aphid therefore they are introduced on an aphid infested farm to eat up the aphid. Birds, frogs and snakes eat insects, cassava mealy bug can be controlled by a tiny wasp; cats may be used to control rodents that attack stored products.

Chemical pest control method

This is the most effective methods of controlling pest. It involves the use of pesticides, insecticides, rodenticides, fumigants etc to control crop pest.

  1. Pesticides- These are chemicals used to control pest. They can be applied in form of solids, dust or powder, liquid, granules, suspension etc. Examples of pesticides are vetox85, Gamalin 20, Didimac 25 etc.
  2. Insecticides- These refers to chemicals used to control insect pest e.g adrin dust, vetox 85, furadin, landine 20 etc.
  3. Rodenticides- These are chemicals used to control rodents.
  4. Fumigants- These are usually poisonous vapor, fumes or emulsions used against pest in the stored products, glass houses and in the soil. E.g. phostoxin, methyl bromide, ethylene dichloride, hydrogen cyanide etc.
  5. Nematicides- These are chemicals used to control nematodes. Nematodes are soil born organisms. E.g. nemagon.

5) Quarantine Regulation– This refers to the period of isolation and observation usually placed on imported crops and animal products to check if they are diseased, pest and weed free. It normally last for about two weeks at the quarantine depot which is normally built at the border towns of the country. If these products are free after checking, they are allowed into the country in not, they are sent back.


6) Legislative control- This refers to the prevention of the introduction of foreign pest into the country by government laws. It can also be referred to as prohibition.


7) Sterilization by radiation- This involves exposing the crop products to high temperature artificially or by spreading them under high sunlight intensity so as to destroy pest that attack the crops.

Side effects of the various control measures.

  • Chemicals may cause environmental pollution.
  • When these chemicals enter the streams, pounds, rivers or lakes, they become toxic to the aquatic lives.



  • State 5 disadvantages of using other control measures to control insect pest apart from the chemical method.












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