Homemade Non-Toxic Wasp Spray / Repellant : combine together in a squirt bottle 2 cups of water + 1 teaspoon of peppermint oil + 1 teaspoon of dish soap (optional); wait until early morning or late evening hours when it looks like they’re sleeping, then shake and spray! You might need to apply the solution twice, but they will fall to the ground and die within seconds. Talk about a natural remedy!
Will try this for my roses this year: A tonic for black spot and powdery mildew on roses Roses, while beautiful, are often plagued with black spot or powdery mildew. I mix these ingredients into a tonic, which I spray on my roses: 2 teaspoons of baking soda and 1/2 teaspoon of liquid soap or Murphy's oil soap in 2 quarts of water. The tonic protects the roses for months.