Many techniques can be used to reduce the losses caused by crop pests by preventing their occurrence or reducing their spread to uninfected plants.


Very few plants have yet been produced by plant breeders with the objective of making them unpalatable or undesirable to insects as a source of food, but work in this area is being developed and some success has been achieved with crops such as cotton. Plants which are extremely hairy often deter insects from laying their eggs on the leaf or stem surfaces.


Due to the relatively high temperature of tropical regions, insects reproduce rapidly and several generations may be produced in a short period.

During the dry season, however, many insects are either inactive or in the egg stage. If details of the life-cycle are known, it is possible to select a period for sowing or planting during which the insects most likely to damage specific crops are either not active or are low in numbers.


The use of chemical dressings on seeds is a preventive technique which can kill eggs on the seed surface and give the young seedling protection during the early stages of growth.


Some insects feed on weeds when crop plants are not available. The destruction of this reservoir of infection before a crop is sown or planted will help to prevent the spread of pests.


The destruction of breeding places where insects can reproduce without disturbance is a very effective means of prevention. All large leaves, branches and rubbish should be either burned or placed on the compost heap. Any material which is observed to be infected with insects should be burned as soon as it is seen.


To deter some pests, particularly some rats, some form of barrier such as wire mesh circles may have to be placed around individual plants such as young oil palm seedlings.



The use of chemicals known as insecticides is generally regarded as the main technique available for controlling crop pests, but other measures such as biological and integrated control are also available either as alternative or supplementary techniques. In some instances, such as sterilising soil to destroy nematodes and bacteria, the application of heat is an alternative to the use of chemicals. Removal of larger insects from crops by hand is an acceptable practice on a small-holding or garden scale but this method is not efficient for larger areas. Crop rotation, which has been discussed, is also an effective means of pest control since it serves to reduce the incidence of pests which feed on the stems and leaves of plants as well as the roots. The planting of crops which are not used as food by some nematodes as a means of reducing their numbers.


The types of dusting and spraying equipment which are available has already been referred to in

The main objectives of these techniques are to cover both sides of the leaves with a chemical which will be poisonous to the insects which come into contact with it or which feed on the leaves covered with the chemical. The application of dusts is often more effective when the leaves of the crop are moist, this helps the particles to remain in contact with the leaf surface. Spraying is best carried out in dull weather since application during very hot sunny weather may sometimes cause scorching of the leaf surface.


Predators are insects which feed on smaller insects and rarely damage plants. If these predators can be encouraged to reproduce, the pests on which they feed will rapidly fall in numbers. This technique is, however, difficult to follow in practice since the preservation of the correct balance between predator and pest is difficult to maintain. If the pests are entirely eliminated, the predators will also die of starvation.


In some instances, chemicals which are poisonous to insects can be mixed with substances which are attractive to them, such as bran. Placing baits between rows of plants or near the growing points of trees may be the most effective means of controlling some of the larger insects such as rhinoceros beetle which damages coconuts.


For nursery use, soil which is free from insects and nematodes is sometimes required. This may be achieved by either heating the soil to a temperature of 82-100°C for about 2 hours or by soaking the soil with chemicals specially recommended for soil sterilisation.


Some insects are particularly harmful during the harvest period when crops are in store. Since they are, by this stage, normally enclosed in bags or other types of container, control is difficult. Fumigation is, however, an effective means of reducing the level of infestation by many weevils and other storage pests.

Smokes and vapours which are poisonous to these insects are introduced into the store which should be carefully sealed to prevent leakage of poisonous fumes. As with all pest control techniques, safety precautions are most important.


Since the cost of chemicals for controlling pests very high, the concept of integrated control is being actively investigated in many parts of the world. The main objective of this technique is to reduce dependence on chemical methods of controlling both pests and diseases by combining spraying or dusting with other techniques of control or prevention which are available. These include sowing or planting when the pest or disease is least active, the maintenance of high standards of farm and garden hygiene, using resistant cultivars, crop rotation, good  cultivation methods to ensure the production of vigorous plants which are less liable to attack than weak ones and, where really essential, the use of chemicals to control pests or diseases. The effective combination of these techniques results in a significant reduction in the quantity of chemicals required in pest or disease control.

PREVENTION OF CROP PESTS & CONTROL MEASURES (Examples And Explanation) PREVENTION OF CROP PESTS & CONTROL MEASURES (Examples And Explanation) Reviewed by Admin on November 10, 2022 Rating: 5

No comments:

Powered by Blogger.