Pest Control

Pest control is a continuous process to mitigate pest populations to a level that does not impact crop yields, while keeping pesticide use at a minimum. It is important to use a mix of methods such as chemical, physical, mechanical, biological, and cultural together to manage pest control. The objective is to ensure healthy crop growth with as many natural pest control systems in place. It is important to incorporate pest planning and prepare preventative measures during the crop planning phase.

The process of pest control begins with observing to distinguish the type of pest. Then the economic injury level (EIL) must be determined, which sets the economic threshold (ET). The EIL refers to the lowest quantity of pests resulting in yield loss equivalent to the cost of managing the pests. The economic threshold is the maximum quantity of pests allowed before management is required to keep pest quantities below the EIL. This threshold is used to determine when to start managing pests.

After determining the type of pest(s) and approximate quantity, the next step is to identify when/if the pests will be a problem and the ideal method of pest control.

Pest Control Methods

The control topics of focus here are chemical, physical, mechanical, biological, and cultural (preventative) processes.

Chemical controls mainly revolve around pesticide use which are sprayed by hand, plane, or truck. Pesticides can contaminate surface and groundwater through agricultural runoff, and also have negative side effects on humans and animals since cash crops get sprayed as well. There are also restrictions on pesticide use in certain areas.

Physical and mechanical methods can be labour intensive as they require pests to be eliminated by physically removing or attacking them. Other physical and mechanical controls such as setting up barriers, traps, and using row covers can be used to protect crops from pests.

Biological controls focus on natural practices available in the environment such as predators and parasites that prey on pests. To attract predators or parasites, setting up filter strips with a variety of natural plants close to crop zones can be advantageous. Predators can also be released in the crop area, where they may establish and remain close as the pests are considered a food source. Another biological method focuses on developing resistant cultivars through genetic modification. Three methods in which this happens include:

  • Antibiosis – breeding plants with low defensive properties with those that have high defensive properties, like allelochemicals which are found in many cover crops
  • Antixenosis – genetically altering plants to have physical properties that repel pests, such as hairs on the leaves or stems, waxes, or strengthening the epidermis to discourage pests from using the crop as a food source
  • Tolerance – Genetically increasing the tolerance of a plant’s genome to withstand pest attacks

Cultural (preventative) controls attempt to make living conditions difficult for pests in crop zones. Some methods include tillage, plant sanitation, altering irrigation methods, and removing diseased plants for spread prevention.

Organic pest control can use any of the above methods other than chemical controls.