Crop pests are one of the most serious threats to successful farming. They include insects, rodents, birds, nematodes, and even certain fungi that attack and damage crops at various stages of growth, reducing yield, quality, and profit.
Without effective prevention and control strategies, these pests can lead to major economic losses and food shortages.
Pest prevention and control refers to the practices and techniques used to protect crops from these harmful organisms. It involves a combination of cultural, mechanical, biological, and chemical methods, all aimed at minimising pest populations and their effects.
In this topic, we will explore the different types of crop pests, the damage they cause, and the most practical and sustainable ways to prevent and control them on the farm.
Methods of Pest Control
Crop pests can be prevented or controlled through the following methods:
- Physical control
- Cultural control
- Biological control
- Chemical control
PHYSICAL CONTROL
This method involves physically removing or excluding pests from the crop. It can include techniques such as handpicking pests, using traps or barriers, erecting fences or nets, and employing mechanical methods like ploughing or mowing to disrupt pest life cycles.
This involves the physical removal of pests by:
- Hand picking of insects and larvae
- Setting traps to catch rodents
- Shooting rodents with a gun
- Fencing around the farm with wire nets.
- Use of a scarecrow.
CULTURAL CONTROL
Cultural control refers to agricultural practices that reduce pest populations or minimise their impact. Examples include crop rotation, which helps break pest life cycles and reduces pest buildup, and selecting pest-resistant crop varieties. Proper irrigation, fertilisation, and maintaining optimal plant health can also enhance crop resilience to pests.
This method involves the use of farm practices to prevent or control pests. Examples of cultural control are:
- Practising crop rotation
- Use of pest-resistant varieties of crops
- Appropriate tillage operations
- Burning crop residues
- Timely planting of crops
- Proper weeding or sanitation
- Timely harvesting
- Close season practices (no living plant is allowed for a certain period).
BIOLOGICAL CONTROL
This involves the introduction of natural enemies of pests to control or keep the pest population under control. Such enemies eat up or feed on these pests, thereby reducing the population of the pests.
This method also involves using natural enemies of pests to control their populations. Predators, parasites, and pathogens that naturally attack pests can be introduced or conserved in the crop environment. For instance, ladybugs feed on aphids, and certain wasps lay their eggs inside caterpillars. This method promotes ecological balance and reduces the reliance on pesticides.
CHEMICAL CONTROL
Chemical control involves the use of pesticides to kill or repel pests. Pesticides can be insecticides (targeting insects), herbicides (targeting weeds), fungicides (targeting fungal diseases), or rodenticides (targeting rodents). While chemical control can be effective, it is important to use pesticides judiciously and follow safety guidelines to minimise environmental and health risks.
Examples of chemicals used to control pests are:
- Insecticides – for controlling insect pests, e.g. grasshoppers
- Rodenticides – chemical control for rodents such as rats
- Avicides – for controlling bird pests
- Nematicides – chemicals used to control nematodes. e.g. worms
It’s worth noting that integrated pest management (IPM) is a holistic approach that combines multiple control methods to effectively manage pests while minimising environmental impact and promoting sustainable agriculture. IPM emphasises the use of non-chemical methods whenever possible and reserves pesticide use as a last resort.
FORMS OR GROUPS OF INSECTICIDES
The four groups and the mode of action are:
| Group | Mode of action |
| 1. Powder | Contact |
| 2. Liquid | Systemic |
| 3. Granules | Stomach (Ingestion) |
| 4. Gas | Fumigation |
SIDE EFFECTS OF THE VARIOUS PREVENTIVE AND CONTROL METHODS OF DISEASES AND PESTS OF CROPS
Use of these control methods has its effect; these effects include
- Death of some beneficial insect and soil organisms, toxic exposure to animals and man, chemical residue in the environment, washing away of chemicals into aquatic life, etc., when the chemical control method is employed.
- Organisms introduced may attack cultivated crops or stored grains, predators might not feed on the targeted pest and deviate to feeding on beneficial organisms, and the activities of new organisms might cause an ecosystem imbalance when a biological control method is employed.
- When the cultural control method is employed, the use of the bush burning method might get out of hand, thereby destroying soil structure, spreading to other farms, loss of organic matter and leading to the death of beneficial microbes.
GENERAL EVALUATION
- What are insecticides?
- List the three forms of insecticides and their mode of action
- What are avicides, rodenticides and nematicides used to control
- List five economic importance of crop pests.
See also
PESTS OF CROPS | MEANING, TYPES, CLASSIFICATION, AND IMPORTANCE
DISEASES OF CROPS | MEANING, CAUSES, EFFECTS, CONTROL
FLORICULTURE – ORNAMENTAL PLANTS | IMPORTANCE, SPECIES, CULTIVATION, SOURCES, MAINTENANCE