Growing your own vegetables can be a rewarding and healthy hobby, but it also comes with some challenges. Pests and diseases can attack your plants and reduce your harvest, or even ruin it completely. Fortunately, there are some simple ways to prevent and control these problems and keep your garden healthy and productive. Most problems can be treated but as the old saying goes “Prevention is better than cure” so to start we will look at simple things you can do to cut the chances of falling victim to pests or disease in the first place.
Tips to Prevent Pests or Disease
- Choose the right plants for your location and season. Plants have different preferences for soil, sun, water, and temperature. Try to grow plants that are suited to your climate and conditions as they will be more resistant to stress and less likely be attacked by pests or suffer disease.
- Rotate your crops every year. Planting the same crops in the same spot year after year can deplete the soil of nutrients and encourage the buildup of pests and diseases that target those crops. By rotating your crops, you can break the pest and disease cycles and improve the soil health. For example, you can divide your garden into four sections and plant a different crop family in each section every year. You can plant beans or peas in one, cabbages or broccoli in the next, potatoes in the third and onions in the last. Then the following three years switch sections so you only ever grow the same type of vegetables in a plot once every four years.
- Try companion planting. Some plants can benefit from growing near other plants, either by repelling pests, attracting beneficial insects, improving soil quality, or enhancing flavour. For example, marigolds can deter nematodes and aphids, while basil can repel insects and improve the taste and growth of tomatoes. You can also plant flowers and herbs among your vegetables to attract pollinators and predators of pests, such as bees, ladybirds and lacewings.
- Keep your garden clean and tidy. Remove any weeds, fallen leaves, rotten fruits, or diseased plants from your garden, as they can harbour pests and diseases and compete with your crops for nutrients and water. You can also mulch your soil with organic matter, such as straw, grass clippings, or compost, to suppress weeds, retain moisture, and add nutrients.
- Monitor your plants regularly and act promptly. Check your plants at least once a week for any signs of pests or diseases, such as holes, spots, wilting, curling, or discoloration. If you notice any problems, identify the cause and treat it as soon as possible. You can use natural remedies, such as neem oil, garlic spray, or baking soda solution, to control mild infestations or infections. For more serious cases, you may need to remove the affected plants or use organic pesticides or fungicides that are approved and suitable for that type of crop.
Common Pests and Diseases
Our vegetables face a variety of threats with the main ones being as follows –
- Slugs and snails. There are around 40 types of slugs and 100 types of snails in the UK. They cause damage by feeding on the leaves, stems, and roots of many types of vegetables, especially lettuce, cabbage, beans, and peas. They can also transmit fungal and bacterial diseases. You can control them by using barriers, traps, encouraging natural predators, or pellets.
- Aphids. These are tiny insects that suck the sap from the plant tissues, causing distortion, stunting, and yellowing. They can also spread viruses and attract ants. You can control them by spraying with water, soap, or oil, or by growing plants in your garden that will encourage beneficial insects that eat aphids, such as ladybirds, lacewings, or hoverflies.
- Cabbage Whitefly. These are small white insects that infest brassica crops, such as cabbage, broccoli, cauliflower, and kale. On cabbages and cauliflowers, they are often found on outside leaves and aren’t always a major problem, but they are more of an issue when they attack kale where they affect younger leaves that are the best to eat. The whitefly lay their eggs on the plants leaves where they suck the sap from the plant and cover it with a sticky substance called honeydew. You may choose to tolerate it on cabbages if its not severe but if you wish to treat it you have several options. The simplest is to wash them off using a hose or you could spray them with an insect soap or neem oil. You must be thorough when doing this and you may have to do it more than once. You could also remove the infected outer leaves or use yellow sticky traps. These traps are effective against whiteflies, fungus gnats and aphids. A bonus of these traps is they using them can allow you to spot an infestation before it becomes a major problem. Finally, you can add plants to your garden that will attract insects that are natural predators of whiteflies like spiders, ladybirds and hover flies.
- Carrot fly. These are small black flies that lay eggs near the roots of carrot, parsnip, celery, and parsley plants. The larvae burrow into the roots, causing damage, deformity, and rotting. They usually appear around the middle of May and lay their eggs in the soil around your cop of carrots. When the larvae appear, they tunnel into the root. The most of obvious sign of damage is usually rusty brown scars around the tap root of the affected vegetable. To minimize the risks of carrot fly there are several options. You can use a physical barrier like a fine mesh net or sheet to protect the crop or take steps to attract beneficial insects such as ground beetles. Carrot fly can over winter in the ground so crop rotation would ensure that you wont sow a new carrot crop in soil that is already infested from the previous season. Some varieties of carrot are less vulnerable to carrot fly so you can choose those and you could also plan your sowing so that it avoids the times when they are at their peak. Carrot fly find the carrots by smell and can detect a crop from a fair distance. Planting other strong scented crops like onions, leeks and garlic can prevent them detecting your vegetables.
- Clubroot. This is a fungal disease that affects brassica crops, causing the roots to swell and distort, and the plants to wilt and die. It can persist in the soil for many years. Using lime on your soil to increase the pH will reduce spores and making sure the ground is well drained might also help. You should also keep the area well weeded. There is however no cure for clubroot and ultimately the solution could be to avoid growing the types of vegetables that it affects.
- Blight. This is a fungal disease that affects potatoes and tomatoes, causing the leaves, stems, and fruits to develop brown spots and rot. It can spread rapidly in wet and humid conditions. To minimise the chances of them affecting your tomatoes there are a few steps you can take. Firstly, there are some varieties that have an element to resistance to blight. They can still catch it but are more likely to survive and produce edible fruit. Blight appears in wet conditions so try to keep the plants dry and water them in the morning, so they aren’t wet overnight. With potatoes you may do better with early varieties but if they do get affected you can slow blights progress by removing the infected leaves. Rotating your crops is also a good idea but don’t grow tomatoes where the potatoes were or vice versa.
- Onion fly. These are similar to carrot fly, but they target onion, leek, garlic, and shallot plants. The larvae feed on the bulbs, causing them to rot and collapse. To protect against onion fly you can cover the crops with fleece or netting or use yellow sticky traps to catch them. There are also nematodes available to use against them. Finally, you can try planting mint nearby as a companion plant. Its strong smell may help repel the flies.
- Powdery mildew. This is a very common fungal disease that affects many crops, especially peas, beans, courgettes, and cucumbers. It causes a white powdery coating on the leaves, stems, and fruits, reducing photosynthesis and yield. There are varieties of plants that have some resistance to mildew so you can check that before you buy your seeds or plants. You can purchase a fungicide but there are also homemade treatments that may work. A simple milk solution of around 1 part milk to 3 parts water is one option and another is to make a solution with baking soda and liquid soap. You should remove any badly affected leaves or plants.
- Cutworms. These are the caterpillars of several species of nocturnal moths that feed on the stems and roots of young plants, cutting them off at the soil level. They can affect many crops, especially brassicas, lettuce, and celery. Sometimes you will not notice cutworms and unless you have a serious infestation you may well choose to do nothing but if you do want to prevent or control them you should keep your vegetables well-watered and the area well weeded. Using a fleece or insect proof netting to grow your vegetables can also reduce the numbers of caterpillars. Encouraging natural predators such as birds, spiders and ground beetles is a good way to control numbers. Finally, there are nematodes on the market if you wish.
Conclusion
Pests and diseases are inevitable challenges for any vegetable gardener, but they can be prevented and treated with some simple strategies. Some issues with pests and diseased plants are an inevitable part of growing vegetables but by following these tips you can minimise these and enjoy a bountiful and rewarding harvest from your vegetable garden.