The Different Methods for Controlling Crop Pests

Pest control is guided by several philosophies. However, there are several methods for controlling crop pests, namely: preventive (prophylactic) control and curative control. In this article, we'll cover only preventive methods for controlling crop pests.

Preventive control

Its purpose is to prevent pests from attacking plants, and to prevent the introduction of parasites (organisms living at the expense of another).

This method focuses on pest nature and behavior. It aims to stimulate the activity of natural enemies (parasitoids, predators, entomopathogenic fungi, mites) or antagonistic organisms, or to strengthen plants' resistance or tolerance to pests and diseases. The effectiveness of a preventive plant protection strategy relies on understanding factors such as the soil, the plants, the pests and their natural enemies, and the agro-ecosystem (biotope (a defined biological environment: field, water, plant, offering stable habitat conditions) + biocenosis (all living organisms of every species, plant and animal, coexisting in a defined space that provides the external conditions needed for their life)).

Understanding the agro-ecosystem

Pests and their natural enemies

The biology of pests and their natural enemies

Pest and natural-enemy activity by season (dry, humid). This helps determine sowing dates, whether early, late, or staggered.

The season or growth stage of the crops

The conditions that favor pest development (weather conditions).

3.1.2 Plants and soil

A nutrient deficiency or excess can cause an imbalance that makes the plant more vulnerable to attack.

The site, soil structure (how sand, silt, and clay particles are arranged relative to each other to form aggregates), nutrient content, and farming practices all have a decisive effect on plants' physiological state.

Example: In the mite Tetranychus urticae and in locusts, the population increases when the nitrogen content in leaves is high.

Strengthening plant resistance

Internal factors

External factors (appropriate farming practices)

Appropriate farming practices are the set of rules to follow when establishing and managing crops, so as to optimize agricultural production while minimizing the risks associated with these practices, both for people and for the environment.

Farming practices

=> Soil improvement (good fertilization, amendments)

Soil fertilization: supplying the soil with nutrients (fertilizer, composting, green manure, fallowing).

Fertilizers contribute to plant nutrition and can come in different forms: granules, powder, sticks, liquid...

=> Mineral fertilizers

1. Simple fertilizers:

Element - Fertilizer type

Nitrogen - Urea

Phosphate - Superphosphate

Potassium - Potassium chloride

2. Compound fertilizers

Elements - Fertilizer type

Binary - NP, PK, NK

Ternary - NPK

3. Organic fertilizers

Adds organic matter to the soil. Organic matter in the soil helps create a favorable environment for soil organisms. It's a source of nutrients, has a water-holding capacity that helps regulate the soil's water system, acts as a buffer against pH changes, contributes to the soil's physical structure by forming organo-mineral complexes, and helps that structure resist erosion by binding soil particles together. Maintaining this structure supports the movement of gas and water through the soil. These come from animal or plant by-products: manure, droppings (especially used in livestock areas), ground horn, seaweed, oilseed cake.

4. Organo-mineral fertilizers

These result from mixing organic and mineral fertilizers. They contain at least 1% nitrogen of organic origin (poultry feathers, leather, oilseed cake). They are mainly used in tree crops and vegetable growing. Fertilizers can be supplemented with trace elements (boron, copper, iron, manganese, molybdenum, zinc, etc.) to address specific deficiencies.

=> Amendments:

This means applying a fertilizing product intended to improve soil quality (in terms of structure and acidity). It can involve either basic amendments, which act on the physical and chemical properties of the soil (for example on pH) to create an environment more suited to growing a crop, or organic amendments, which also act on the soil's microbial life.

Soil structure is defined as the arrangement of particles and associated pores within the soil.

Crop rotation

The basic principle of crop rotation is to separate the pest from its host plant in space and time. This interrupts the pest's biological cycle by introducing a non-host plant, generally one from a different family.

Building a rotation is based on two principles:

• The plants don't belong to the same family
• Choosing species that share few common pests

This approach is effective for controlling soil-borne pests (nematodes, cutworms).

Polyculture

It has been shown that pest populations, and therefore the damage they cause, are greater on farms growing a single crop than on those growing several crops. Plant species diversity should therefore be increased. It can also be increased by setting up trap crops and bait crops (plants that shelter beneficial organisms).

Selecting resistant varieties

This means using genetic variability to improve the performance of varieties exposed to pest attacks.

Field and soil hygiene

Weeding

Hoeing

Clearing

Pruning

Controlling plant imports and trade

Plants or plant products brought into Cameroon may carry harmful organisms. Phytosanitary inspection checks that these plants pose no risk to crops or to the environment.