Crop Plants: Pest Control
Using pest control to increase crop yields
- Pests such as insects and other animals can damage crops by eating them
- Weeds can outcompete crop plants for space, water and soil nutrients
- Fungi can infect crop plants and spread disease which can affect growth and yield
- All of these can be controlled by using pesticides (chemical control) or by introducing other species (biological control)
- Examples of pesticides include:
- Insecticides kill insect pests
- Herbicides kill plant pests
- Fungicides kill fungal pests
Advantages and disadvantages of pesticides table
Advantages | Disadvantages |
Easily accessible and relatively cheap | Organisms they are meant to kill can develop resistance to them |
Have an immediate effect | They are non-specific chemicals and can often kill other beneficial organisms (e.g., some insecticides might kill bees, which are important pollinators of crops) |
Kills the entire population of pests | They can be persistent chemicals – this means they do not break down in the body and can accumulate in great concentrations at the top of food chains and harm top predators (known as bioaccumulation) |
Need to be repeatedly applied |
Biological control
- Biological control involves using a natural predator to eat the pest species and therefore reduce the impact of the pest on crop yields
- This can happen naturally – for example, ladybirds eat aphids
- Usually, a species is introduced specifically to prey on the pest species – for example, parasitic wasps can control whitefly in glasshouse tomato crops
- As they are based on a predator-prey cycle, they do not completely remove a pest, but keep it at lower levels
Advantages and disadvantages of biological control table
Advantages | Disadvantages |
Natural method - no pollution | May eat other organisms instead of the pest |
No resistance | Takes a longer period of time to be effective |
Can target specific species | Cannot kill entire population - some pests will always be present |
Long lasting | May not adapt to new environment or may move out of the area |
Does not need to be repeatedly applied | May become a pest itself |