Common vegetable garden diseases

5th August, 2023

Unfortunately, there is no guarantee that the seeds you buy will result in a plentiful harvest, there are numerous diseases that can badly affect crops. Below are some of the main vegetable plant diseases to look out for, and also some organic gardening methods to protect your plants from them. 

1. Tomato blight: Caused by a fungal spore that thrives in warm, moist conditions, tomato blight can lead to the rapid decay of tomato plants. The best way to prevent it is to maintain good air circulation between plants, avoid overhead watering (point the watering can close to the base of the plant), and remove infected foliage immediately.

2. Clubroot: A soil-borne disease that attacks brassica crops (such as broccoli, cauliflower, and cabbage), clubroot can cause stunted growth and distorted roots. To prevent it, rotate your crops, add lime to soil to maintain a pH of 7.2-7.4, and avoid planting brassicas in infected soil.

3. Potato blight: A common problem in wet summers, potato blight can cause the rapid decay of the potato plant. To prevent it, plant resistant varieties, maintain good air circulation, and remove infected foliage as soon as it appears.

4. Powdery mildew: A fungal disease that causes a white, powdery coating on leaves, powdery mildew can lead to plant stress and a reduced harvest. Control methods include spraying affected plants with a mixture of water and bicarbonate of soda, or using a milk spray solution.

5. Tomato Leaf Curl Virus – Tomato leaf curl virus is spread by whiteflies and causes the leaves on tomato plants to curl upward. Use yellow sticky traps to capture whiteflies, companion plant with marigold flowers, remove infected plants, and introduce parasitic wasps to control the whitefly population. 

6. Verticillium Wilt – Verticillium wilt is a fungal disease that affects tomatoes, peppers, and potatoes. It causes the leaves to wilt and die, so cut off infected leaves and do not compost them. Rotate crops, and use crop covers to prevent spores from being spread.

7. Scab – Scab is a common potato disease that causes raised, black blemishes on the skins of the tubers. Improve soil drainage by adding organic matter and rotate crops to prevent the disease from spreading. 

8. Grey Mould – Grey mould, or botrytis, is a fluffy grey fungus that can attack many different plants. It thrives in damp conditions and causes wilting and rotting of leaves and flowers. Remove infected parts of the plant, improve air circulation, and practice good hygiene in the garden.