If you are growing a Tower Garden, you will experience Powdery Mildew at some point. It’s not a case of if, but rather when. But what is powdery mildew and how do you get rid of it?
According to Master Gardener Jim Cooper of the Washington State University Extension, it has been estimated that, when you factor in the total loss of crop yields and plant growth, powdery mildew produces the greatest losses of any single plant disease throughout farmers’ fields as well as home gardens.
What is Powdery Mildew?
Powdery mildew is a fungal disease that affects a wide range of plants, including ornamental plants, trees, and crops grown in the Tower Garden. It appears as a white or grayish powdery coating on the leaves, stems, and flowers of infected plants. Powdery mildew is caused by various species of fungi belonging to the Erysiphales order. The fungi infect the plant by forming spores that are carried by the wind or water and settle on the plant’s surface. Once the spores germinate, the fungus grows and spreads by producing more spores.
These spores can also be spread by us, so it’s important to be cautious when dealing with and treating plants affected by powdery mildew. Carefully wash your hands and all tools used to prune and harvest to reduce the chance of you spreading it to other crops.
Why is Powdery Mildew a Problem?
Powdery mildew can weaken and damage plants by reducing their ability to photosynthesize, which can result in reduced growth, yield, and quality. It can also cause premature leaf drop and make the plant more susceptible to other diseases and pests.
Are Some Plants More Prone to Powdery Mildew?
Yes! Squash, Cucumber, Melon, Pumpkin, Tomato, Pepper, Strawberry, and Dill are some of the Tower Garden crops that are most prone to powdery mildew. When growing these crops it’s a good idea to look for and grow hybrid varieties that are more resistant to powdery mildew, especially if you live in an area with hot and humid summers. Many of the seedlings we offer at www.livingtowerseedlings.com are resistant to powdery mildew.
Remember though! Resistant doesn’t mean immune and just because it isn’t prone to powdery mildew, doesn’t mean it won’t ever be affected. You can still spread it! You will still want to follow the steps below.
How Can You Prevent Powdery Mildew?
Powdery mildew is often more prevalent in warm, humid conditions and can be prevented by maintaining good plant hygiene. Ensure you are pruning plants so as to avoid overcrowding as this promotes good air circulation. If growing inside you can add a fan to increase air circulation. As I mentioned earlier, it’s a good idea to grow varieties that are powdery mildew resistant.
How Can I Treat Powdery Mildew on My Crops?
Here are some steps you can take to treat powdery mildew:
- Remove infected leaves: If you notice powdery mildew on your plants, remove any infected leaves and dispose of them in the trash. Do not compost infected plant material as this may spread the disease. Remember to wash hands and tools after removing infected leaves.
- Improve air circulation: Powdery mildew thrives in humid, stagnant air, so improving air circulation can help prevent the spread of the disease. You can do this by pruning your plants to increase airflow or by using a fan to circulate air around your plants.
- Use fungicides: If the powdery mildew is severe, you may need to use a fungicide. There are several fungicides available that are effective against powdery mildew, including neem oil, sulfur, and potassium bicarbonate (not to be confused with Sodium bicarbonate or Baking Soda which is not a good fungicide). We also offer Garden Friendly Fungicide on our website. Be sure to follow the instructions on the label carefully when using any fungicide.
- Milk. Yes, you can use Milk! Spraying milk on areas of plants that display symptoms will help to control powdery mildew, particularly if it is applied at the early stages of an infection. This technique is used by many organic growers around the world and has been found to be effective in studies conducted over the course of over 60 years on tomatoes, grape vines, apples, pumpkins and other types of winter squash, cucumbers, zucchini, and other types of plants. Results of one the above-referenced study on pumpkins and acorn squash indicated that this readily available product could provide control similar to that achieved via the use of conventional chemical fungicides, whereas applications of compost tea were not found to be effective. Treatment with milk was most effective at the early stages of infection.The common advice is to dilute milk at a ratio of 1:10 with water and spray it on your plants at the first sign of infection, however, according to the available research to date, higher concentrations of milk may prove to be the most effective. Try a 50/50 mix of liquid milk to water for moderate to severe infections, or even full-strength milk if you don’t have a large area to cover.
By taking these steps, you can effectively treat powdery mildew and help prevent it from spreading to other plants in your Tower Garden.
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