What to Do About Mildew
Powdery mildew is a pretty common problem in many gardens. It shows up as a white powdery film on the leaves of our plants, and if left unchecked, it can really affect how much fruit our plants produce, as well as the quality of the fruit. It is a fungal disease that can affect almost any plant but is particularly common on squash, pumpkins, cucumbers, melons, tomatoes, eggplants, peppers, roses, beans and peas.
The spores of powdery mildew can spread to and around your garden with the wind. Generally, powdery mildew shows up later in the growing season, and it looks like small powdery white spots on the leaves. It will eventually spread, covering the whole leaf, causing it to turn yellow and likely drop-off.
Mildew shows up in specific, although unfortunately common conditions. It likes hot weather with high humidity and dry soil, which can be common in Powell River. This often happens after we’ve had a dry spell with no rain. Powdery mildew usually shows up on young leaves, as it likes fresh, young growth the best. It will eventually appear on flower buds as well and may cause them to shrivel without even opening. The spores of powdery mildew can overwinter on plant material, and in the soil, so it can be challenging to rid your garden of it entirely.
You can work to prevent powdery mildew, but you’ll likely still need to treat it as well. As with most garden challenges, prevention and treatment are both critical.
To prevent powdery mildew, you can plant mildew-resistant varieties of plants in sunny locations. You can prune plants to improve air circulation around the leaves. Watering using drip irrigation or soaker hoses usually helps because then the spores don’t splash up onto the leaves from the soil below. Watering in the morning will also make sure the humidity level doesn’t stay too high all day. Using stakes or cages to support your plants can also help keep the leaves up, allowing better airflow.
To treat powdery mildew, you have a few different options. When you see the signs, immediately remove the leaves affected by it and dispose of them in the garbage. Do not add them to your compost bin. Be sure to sanitize your pruners after each cut with a bleach mixture to prevent further spreading the spores.
One of the most effective treatment options is spraying the leaves with a milk mixture. Depending on the severity of the mildew, you can mix milk with water. For a mild case that you’ve caught early, you may only need 1 part milk to 10 parts water. If you’ve got quite a lot of mildew, you can safely mix it as strong as 4 parts milk to 6 parts water. Apply this mixture liberally to the leaves of your plants every 10-14 days, making sure to thoroughly spray the tops and bottoms of leaves.
There are fungicides you can use to treat powdery mildew. Usually, these products contain sulphur, copper, or potassium bicarbonate. These products are also effective and may be an excellent place to start if you have powdery mildew on everything. Most of these products need to be applied every 7-10 days to control the mildew. Make sure to read the instructions carefully if you choose to use a commercial fungicide.
