Powdery Mildew is a fungal disease which causes white, powdery growth on a plants' foliage. Almost no plant type is fully immune to the disease although some are more susceptible than others. These include vegetables such as beans, peas, peppers, squash, cucumbers, and pumpkins. If powdery mildew appears on your plants it’s rarely fatal, however you should try and treat diseased plants as soon as you can to stop further infection.
Early stages of powdery mildew will leave small circles of white/grey powder spots on the foliage, stems or in some cases fruit. If left untreated it can spread throughout the foliage and drain nutrients from plants, leading to withered leaves. In more serious cases it can affect your yields and the flavour of your fruit and vegetables.
Powdery mildew can often be mistaken with other powdery-type plant diseases such as downy mildew. Downy mildew is often browner/greyer in colour and tends to attack the undersides of leaves. They thrive in different growing conditions to each other to, so with little research you should be able to distinguish between the two.
Powdery mildew thrives in warm and dry conditions. The spores initially form when foliage is dry, lighting is low and there is some humidity in the air. It is worth having a good check over of plants in late spring or early summer as because of the weather this is when plants are most susceptible. Fresh new growth is most vulnerable so be sure to check the whole plant.
How To Reduce The Chances Of Powdery Mildew
Even though there is no chemical control, there are several things gardeners can do to prevent infection:
- A key step to prevent powdery mildew is to grow mildew-resistant varieties. Some of our favourite seed varieties include Courgette Defender F1, Pumpkin Cargo F1, Cucumber Burpless Tasty Green and Pea Shiraz.
- When planning your growing space ensure plants have appropriate spacing to allow enough airflow throughout your crops. It’s also important to make sure plants are receiving sufficient light. Avoid planting susceptible plant types in shaded areas.
- Keep plants well pruned to maintain light and airflow.
- If early signs of mildew are present remove any dead or diseased foliage as soon as possible. DO NOT put these in your normal garden compost.
- Use preventative treatments. One of our customer favourites is our bug and mildew spray. Follow manufacturers application instructions and ensure that the spray is suitable for use on edible crops.
