1. Insects
Insects are the most common type of crop pest. They can cause damage by chewing on leaves, stems, and fruits, or by sucking sap from plants. Some of the most common insect pests include:
- Aphids are small, green insects that feed on the sap of plants. They can cause leaves to curl and yellow, and can also transmit diseases to plants.
- Caterpillars are the larvae of butterflies and moths. They can chew on leaves, stems, and fruits, causing extensive damage to plants.
- Grasshoppers are large, hopping insects that can eat entire plants. They are especially damaging to crops in dry areas.
- Weevils are small, brown insects that feed on the grains of plants. They can cause significant damage to crops, especially in storage.
2. Diseases
Diseases are caused by fungi, bacteria, and viruses. They can cause a variety of symptoms on plants, including:
- Leaf spots are small, brown or black spots on leaves. They can be caused by a variety of fungi and bacteria.
- Powdery mildew is a white or gray fungus that covers the leaves of plants. It can cause leaves to turn yellow and fall off.
- Rust is a red or brown fungus that infects the stems and leaves of plants. It can cause stunted growth and reduced yields.
- Viruses cause a variety of symptoms on plants, including yellowing, stunting, and leaf curling. They can be spread by insects or by contact with infected plants.
3. Weeds
Weeds are plants that grow where they are not wanted. They can compete with crops for water, nutrients, and sunlight, reducing yields. Some of the most common weeds include:
- Annual weeds complete their life cycle in one year. They include species such as pigweed, lamb's-quarters, and chickweed.
- Biennial weeds complete their life cycle in two years. They include species such as burdock, mullein, and thistle.
- Perennial weeds live for more than two years. They have deep root systems that make them difficult to control. Some of the most common perennial weeds include quackgrass, dandelions, and bindweed.
4. Vertebrates
Vertebrates include animals such as birds, rodents, and deer. They can damage crops by eating them, trampling them, or spreading diseases. Some of the most common vertebrate pests include:
- Birds can eat seeds, fruits, and leaves. They can also spread diseases to plants.
- Rodents can gnaw on roots, stems, and fruits. They can also spread diseases to plants.
- Deer can eat entire plants, including leaves, stems, and fruits. They can also trample plants and spread diseases.