Identifying and Controlling Common Plant Pests and Diseases
Aphids
Aphids are tiny, soft-bodied insects that feed on plant sap, causing stunted growth, yellowing leaves, and honeydew excretion. Control aphids by spraying with insecticidal soap or neem oil, or by introducing beneficial insects such as ladybugs and lacewings.
Cabbage Worms
Cabbage worms are the larvae of cabbage butterflies, and they feed on the leaves of cabbage, broccoli, and other cruciferous vegetables. Hand-remove adults and eggs, or use Bacillus thuringiensis (Bt), a biological insecticide that specifically targets cabbage worms.
Spider Mites
Spider mites are tiny, spider-like pests that feed on plant leaves, causing them to turn yellow and drop off. Control spider mites by spraying with horticultural soap or neem oil, or by introducing predatory mites.
Squash Bugs
Squash bugs suck the sap from squash, pumpkin, and zucchini plants, causing wilting and stunted growth. Remove any affected leaves and scout for adults and eggs. Use row covers to prevent squash bugs from reaching plants.
Tomato Hornworms
Tomato hornworms are large, green caterpillars that feed on the leaves and fruit of tomato plants. Hand-remove hornworms or use Bacillus thuringiensis (Bt) to control them.
Whiteflies
Whiteflies are tiny, white insects that feed on the undersides of plant leaves, causing yellowing and wilting. Control whiteflies by monitoring plants regularly, washing them off with water, or using insecticidal soap or neem oil.
Wireworms
Wireworms are the larvae of click beetles, and they feed on the roots of plants, causing stunted growth and wilting. Control wireworms by cultivating the soil to expose them to birds, using decoy traps, or removing and destroying infected crops.
Cucumber Beetles
Cucumber beetles feed on roots, leaves, and flowers of cucumber, squash, and melon plants, and they can also transmit bacterial wilt disease. Control cucumber beetles by using wilt-resistant plants, keeping plants off the ground with trellises, and using insecticides such as Rotenone or Pyrethrum.
Plant Viruses
Plant viruses are microscopic pathogens that can cause a variety of symptoms in plants, including yellowing, mottling, stunting, and wilting. Control plant viruses by removing and destroying infected plants, using disease-resistant varieties, and practicing good sanitation.
Gray Mold
Gray mold is a fungus that affects a wide range of plants, causing leaves to turn gray and moldy. Control gray mold by removing and destroying affected leaves, giving plants plenty of airflow, and using fungicides.
Powdery Mildew
Powdery mildew is a fungus that forms a white powdery coating on plant leaves, causing them to turn yellow and drop off. Control powdery mildew by using fungicides or by spraying plants with a solution of baking soda and water.
Leaf Spot
Leaf spot is a fungal disease that causes brown or black spots on plant leaves. Control leaf spot by using fungicides or by removing and destroying infected leaves.
Additional Tips for Pest and Disease Control
- Monitor your plants regularly for signs of pests and diseases.
- Use organic methods of pest and disease control whenever possible.
- Keep your garden clean and free of debris.
- Rotate crops each year to prevent the buildup of pests and diseases in the soil.
- Use companion planting to deter pests and attract beneficial insects.
- Consult with a local gardening expert or extension agent for specific advice on pest and disease control in your area.
